阅读说明：本技术 具有分段波形转换器的混合型装置 (Hybrid device with segmented waveform converter ) 是由 I·S·弗兰普顿 A·拉森 T·罗特 T·鲍曼 于 2016-10-17 设计创作，主要内容包括：一种设备包括受控场交流发电机或实用电源、分段波形转换器和控制器。电源被配置成生成多相信号。同步逆变器包括在电源的多相信号与输出滤波器之间连接的多个开关。控制器被配置成基于与输出滤波器相关联的测量电量来提供用于开关的控制信号,并且可以向受控场交流发电机提供场控制信号。该设备可以应用于车辆、割草机、零转弯半径割草机或其他类型的机器。(An apparatus includes a controlled field alternator or utility power supply, a segmented waveform converter, and a controller. The power supply is configured to generate a multi-phase signal. The synchronous inverter includes a plurality of switches connected between the polyphase signals of the power supply and the output filter. The controller is configured to provide a control signal for the switch based on a measured electrical quantity associated with the output filter, and may provide a field control signal to the controlled field alternator. The apparatus may be applied to a vehicle, lawn mower, zero turn radius lawn mower, or other type of machine.)

1. An apparatus, the apparatus comprising:

an alternator;

an output drive mechanism; and

at least one synchronous inverter including a plurality of switches connected between the alternator and the output drive mechanism,

wherein the at least one synchronous inverter comprises a first synchronous inverter associated with a first wheel of a vehicle and a second synchronous inverter associated with a second wheel of the vehicle, wherein the first wheel or the second wheel is coupled to the output drive mechanism,

wherein the force from the first wheel causes power to flow from the first synchronous inverter to the second wheel.

2. The apparatus of claim 1, wherein the alternator is of the twin-shaft type comprising an air gap coaxially located on a common plane orthogonal to the axis of rotation of the alternator.

3. The apparatus of claim 1, wherein the output drive mechanism is coupled with a mowing system.

4. The apparatus of claim 1, the apparatus further comprising:

a battery, wherein the at least one synchronous inverter comprises a supplemental synchronous inverter configured to charge the battery.

5. The apparatus of claim 4, wherein the at least one synchronous inverter comprises a synchronous inverter associated with a first wheel of a vehicle and a synchronous inverter associated with a second wheel of the vehicle, wherein the first wheel or the second wheel is coupled to the output drive mechanism.

6. The apparatus of claim 4, wherein power associated with braking the first wheel is transmitted to the battery through the supplemental synchronous inverter for charging the battery.

7. The apparatus of claim 1, the apparatus further comprising:

a direct current output of the at least one synchronous inverter, the at least one synchronous inverter configured to provide a field current to the alternator.

8. The apparatus of claim 1, the apparatus further comprising:

a common bus configured to receive power from a common source for the at least one synchronous inverter.

9. The apparatus of claim 8, wherein the common bus comprises an induction coil for wirelessly receiving power from the common source.

10. The apparatus of claim 1, the apparatus further comprising:

a controller configured to: control signals for the plurality of switches are provided based on a measured electrical quantity associated with the output, and a field control signal is provided to the alternator.

11. The apparatus of claim 10, wherein the controller is configured to calculate a plurality of combinations of available voltages through different settings for the plurality of switches, the connection configuration of the outputs, or the field control signals.

12. An apparatus, the apparatus comprising:

an alternator;

a first output drive mechanism;

a first synchronous inverter associated with a first wheel of a vehicle and including a first plurality of switches connected between the alternator and the first output drive mechanism;

a second output drive mechanism; and

a second synchronous inverter associated with a second wheel of the vehicle and including a second plurality of switches connected between the alternator and the second output drive mechanism,

wherein the force from the first wheel causes power to flow from the first synchronous inverter to the second wheel.

13. The apparatus of claim 12, wherein the alternator is of the dual shaft type including an air gap coaxially located on a common plane orthogonal to an axis of rotation of the alternator.

14. The device of claim 12, wherein the first output drive mechanism is coupled with a mowing system.

15. The apparatus of claim 12, the apparatus further comprising:

a battery; and

a supplemental synchronous inverter configured to charge the battery.

16. The apparatus of claim 12, the apparatus further comprising:

a direct current output of the first synchronous inverter, the first synchronous inverter configured to provide a field current to the alternator.

Technical Field

The present application relates to the field of variable speed generators, and more particularly to an Alternating Current (AC) to AC converter for controlling the output of a controlled field synchronous alternator on a variable speed generator.

Background

The engine-generator set may be referred to as a generator or a generator set, and may include an engine and an alternator or another device for generating electrical energy or power. One or more generators may provide power to a load via a power bus. The power bus, which may be referred to as a generator bus or a common bus, transfers power from the engine-generator set to the load. In many examples, the electrical load on the engine-generator set may vary over time.

The frequency of the output of the synchronous alternator is based on the speed of the engine and the number of generators. To provide a constant output frequency, the prime mover may need to be operated at a fixed speed. The engine may not need to operate at a fixed speed in order to provide sufficient power to the load, but does so with a constant frequency.

While allowing engine speed to be reduced at light loads may reduce wear, fuel consumption, and acoustic emissions from the generator, it is desirable to shift the frequency so that the engine speed is reduced compared to the rated speed.

Drawings

Exemplary embodiments are described herein with reference to the accompanying drawings.

Fig. 1A and 1B illustrate an exemplary engine-generator set including one or more synchronous inverters.

Fig. 2 illustrates an exemplary single-phase segmented waveform converter.

Fig. 3A and 3B illustrate exemplary switches of a segmented waveform converter.

Fig. 4 illustrates an exemplary three-phase segmented waveform converter with alternator field current control.

Fig. 5 illustrates another exemplary three-phase segmented waveform converter.

Fig. 6A illustrates an exemplary pin diagram of an integrated circuit of the segmented waveform converter of fig. 4.

Fig. 6B illustrates an exemplary pin diagram of an integrated circuit of the segmented waveform converter of fig. 5.

FIG. 6C illustrates an exemplary power supply for supplying current to an alternator field.

Fig. 7A and 7B show exemplary single-phase wiring diagrams of the synchronous inverter.

Fig. 8A shows an exemplary low wye wiring diagram of a synchronous inverter.

Fig. 8B shows an exemplary high wye wiring diagram of a synchronous inverter.

Fig. 9 shows an exemplary low triangular wiring diagram of a synchronous inverter.

Fig. 10 shows a synchronous inverter type generator configured to start an engine using an alternator and a synchronous inverter.

FIG. 11A shows an exemplary engine torque curve.

FIG. 11B illustrates an exemplary power curve for the engine.

FIG. 12A shows a graph of alternator losses in an exemplary controlled field alternator on a variable speed generator with a synchronous inverter.

Fig. 12B shows an exemplary engine speed versus load curve and system loss curve for a system including a synchronous inverter.

Fig. 13 shows an exemplary side view of a two-shaft alternator.

Fig. 14 illustrates an exemplary block diagram of an exemplary synchronous inverter system.

Fig. 15 illustrates an exemplary block diagram of another exemplary synchronous inverter system.

Fig. 16 illustrates an exemplary controller.

Fig. 17 shows a flow chart of the controller of fig. 15.

Fig. 18 shows an exemplary alternator and two synchronous inverters.

Fig. 19 shows an exemplary alternator and three synchronous inverters.

Fig. 20 shows an exemplary lawn mower implementing a synchronous inverter for battery charging.

Fig. 21 shows an exemplary lawn mower implementing three further synchronous inverters in addition to the synchronous inverter for battery charging.

FIG. 22 illustrates an exemplary lawn mower implementing three synchronized inverters and a common source.

FIG. 23 illustrates an exemplary lawn mower implementing a synchronous inverter and a supplemental synchronous inverter for battery charging and a utility source.

FIG. 24 illustrates an exemplary lawn mower and utility source.

FIG. 25 illustrates an exemplary vehicle including a synchronous inverter.

Fig. 26 shows an exemplary vehicle including a synchronous inverter other than the synchronous inverter for battery charging.

FIG. 27 illustrates an exemplary vehicle including a synchronous inverter and a common source.

Fig. 28 illustrates an exemplary generator system including a synchronous inverter system.

Fig. 29 shows an exemplary generator system including a synchronous inverter system that provides power from a generator in addition to a synchronous inverter that supplies power to a battery.

FIG. 30 illustrates another exemplary generator system having a synchronous inverter.

Fig. 31 shows a flow chart of the operation of the generator controller of fig. 16.

Fig. 32A illustrates an exemplary engine-generator set including a synchronous inverter and an external load device.

Fig. 32B illustrates an exemplary engine-generator set including a synchronous inverter and an electric machine.

FIG. 33 illustrates an exemplary vehicle including a synchronous inverter and at least one electric machine.

FIG. 34 illustrates exemplary sub-assemblies of the vehicle of FIG. 33.

FIG. 35 shows a reverse diagram of the exemplary sub-components of FIG. 34.

Fig. 36 shows a top view of the exemplary subassembly of fig. 34.

Fig. 37 shows a perspective view of the vehicle.

Fig. 38 shows a flow chart for powering a vehicle with a synchronous inverter.

Detailed Description

An Alternating Current (AC) to AC converter converts an AC signal or waveform to another AC signal having different or altered electrical characteristics. The changed electrical characteristic may be voltage, frequency, or other characteristic. Example types of AC-AC electrical converters include cycloconverters, matrix converters, and hybrid converters. A cycloconverter converts an input waveform to a lower frequency output signal by synthesizing segments of the input waveform without a dc link. The cycloconverter may use a Silicon Controlled Rectifier (SCR) as a switch to synthesize the input. The matrix converter utilizes a network of transistors, similarly synthesizing segments in a segmented manner to generate the desired output waveform. The hybrid converter may incorporate a combination of the two approaches described above. Although frequency converters or cycloconverters may allow for correction of the frequency, they operate to control the output of the generator without controlling the input.

Any of these examples may be collectively referred to as a segmented waveform converter. The segmented waveform converter may generate a single phase output from a multi-phase input. The output of the segmented waveform converter may be a four quadrant output, where the segmented waveform converter may transfer active and reactive power in either direction through the segmented waveform converter. A segmented waveform converter generates an output waveform for a segment at a time by directly delivering a combination of one or more of the input signals. High frequency ripple, switching noise, and undesirable distortion of the output can be removed by appropriate filtering of the input waveform. The output waveform is generated by successive fractional sampling of the input voltage. The frequency of sampling defines the length of each segment. The frequency of sampling may be significantly higher than the frequency of the input waveform and the frequency of the output waveform. For example, an input frequency of 200Hz and an output frequency of 60Hz may require a sampling and switching frequency of 20kHz in order to provide an acceptable output power quality.

A further advantage achieved by a segmented waveform converter, which is distinct from conventional inverters, is that lower rated components can be used. Compared to conventional rectifiers, segmented waveform converters use more switching elements between the power source and the load. Thus, on average, the current through each of the switching elements becomes less, and the switching elements may have a smaller current or power rating. A lower nominal component can reduce the cost by a lot. The segmented waveform converter may be electrically connected to one or more filters and configured to provide filtered outputs to various loads. Such a segmented waveform converter may be referred to herein as a synchronous inverter.

It is preferable to enable the cycloconverter to control the input voltage and frequency in addition to the output voltage in order to optimise efficiency and provide protection for components in the cycloconverter. Furthermore, many cycloconverters generate Total Harmonic Distortion (THD) of the output voltage due to switching and commutation noise. Depending on the application, this total harmonic distortion may be undesirable.

Fig. 1A shows an exemplary engine-generator set 10a, the engine-generator set 10a including a synchronous inverter 11, an engine 12, and an alternator 13. The synchronous inverter may comprise at least one controller (i.e. microprocessor) for controlling the switching network of the segmented waveform converter. The alternator 13 may be a controlled field alternator in which a generator controller (field current controller) actively controls the field current to regulate the output of the alternator 13. The synchronous inverter controller and the field current controller may be the same device or different devices. The output device 14 of the synchronous inverter provides an output waveform to a load or other device.

The controlled field alternator 13 is configured to generate a multi-phase signal through operation of the engine 12. The controlled field alternator 13 may include an exciter armature for generating a field current. As the exciter armature rotates in the magnetic flux, a time-varying voltage is induced in the windings of the exciter armature. The output from the exciter armature is connected to the main field portion of the generator. This connection may be accomplished with or without brushes and slip rings. The output field current of the exciter provides a magnetic field in the rotor field of the generator. As the field portion of the alternator rotates relative to the stator, the magnetic flux passes through and across the alternator stator windings, thereby producing a time-varying voltage. The field current from the exciter armature output may be rectified or otherwise controlled.

The output of the alternator 13 may be a three-phase signal. The phases of the multi-phase signals may cancel each other out by a predetermined angle (e.g., 120 degrees or 2 x pi/3 radians). The multi-phase signal may vary in amplitude and frequency.

The controlled field alternator 13 provides the multiphase signal to a segmented waveform converter, which may comprise a matrix cycloconverter, of the synchronous inverter 11. The segmented waveform converter includes a switching network that selectively controls the delivery of combinations of the components of the multi-phase signal to the output 14. For example, consider an example in which a multi-phase signal includes two components a and B. The switching network may provide to the output several combinations of these two components, which may include only the a component, only the B component, an added signal of a + B, a subtracted signal of a-B or B-a, and a 0 or null signal that may be realized by a-a or B-B.

Prior to the output 14, the synchronous inverter 11 may include an output filter, and the amount of power may be measured at the output filter by a controller of one or more sensors. The controller of the synchronous inverter 11 may be configured to provide a control signal to the switching network based on the measured amount of power associated with the output filter and to provide an excitation current control signal to the controlled field alternator.

The controller may receive an amount of power from at least one sensor. The controller may perform calculations or consult a look-up table to determine the combination of components of the multi-phase signal to be delivered to the output 14. In one example, the look-up table correlates combinations of available voltages to different settings of the plurality of switches. The available voltage may change over time. In one example, the available voltage varies according to a time-based schedule of expected values. In another example, the available voltage varies according to the measured value.

FIG. 1B shows another exemplary engine-generator set 10B that includes two synchronous inverters 11a and 11B, an engine 12, and an alternator 13. The two synchronous inverters 11a and 11b may be connected through a synchronous path 15.

The two synchronous inverters 11a and 11b are fed by an alternator 13 and are configured to synchronize the output waveforms using a synchronization signal on a synchronization path 15 between the synchronous inverters 11a and 11 b. The synchronization signal may comprise a digital signal that may indicate a peak, a positive or negative zero crossing on the target voltage waveform, or another element of the internal target signal. The synchronization signal may comprise an analog signal indicative of the target waveform, a phase angle indication, or another element of the target output waveform.

The synchronization signal may be a communication signal for conveying a target voltage, a target frequency, an active load, a reactive load, an apparent load, a zero-crossing timestamp, a time synchronization signal, or other information related to the measured output waveform, the target output waveform, or the input from the alternator to the inverter. In one example, one of the synchronous inverters 11a detects a zero-crossing and a slope of the output of the synchronous inverter 11a, wherein the zero-crossing and the slope are transmitted to the other synchronous inverter 11b by using the synchronization signal. The other synchronous inverter 11b may introduce a delay to synchronize with the synchronous inverter 11 a. Various techniques may be used to synchronize the synchronous inverters.

The supplies from the alternator 13 to the synchronous inverters 11a and 11b may be magnetically isolated from each other to allow the inverters to be connected in series, and the two inverters may be allowed to be connected in a center-tapped configuration so that 120 or 240 outputs a voltage as needed. Fig. 2 shows an exemplary synchronous inverter 11 including a segmented waveform converter 20. The segmented waveform converter 20 includes switching networks SW 1-SW 6 and at least one energy storage device. The example shown in fig. 2 includes an inductor 21 and a capacitor 23. Inputs A, B and C to segmented waveform converter 20 are components of the multi-phase AC waveform.

In one example, segmented waveform converter 20 is configured to provide a control signal to each switch related to any combination of two or fewer of the components of the multi-phase input waveform. The control signals may include A, B, C, A-B, A-C, B-C, B-A, C-B, C-A and 0. Other switch configurations may be configured to provide other combinations, such as additive combinations a + B, B + C and a + C, thereby using switch configurations other than the one shown. In another example, segmented waveform converter 20 is configured to provide a set of predetermined outputs based on a combination of components of a multi-phase input waveform. The set of predetermined outputs may include a subtractive combination of only two of the components, including A-B, A-C, B-C, B-A, C-B and C-A. The set of predetermined outputs may comprise 0, any single component (A, B or C), or any subtractive combination of only two of the components.

The controller may access a target output level as a function of time. For example, the target output may be an AC waveform having a particular frequency and/or a particular amplitude. The target output level may be stored as a series of time-based target values. For example, the time value is associated with a target output level (e.g., { time 1, output 1}, { time 2, output 2 }). The target output level may follow a sinusoidal function, and the target output level may be calculated based on the particular voltage and frequency of the output.

The controller may calculate a target electrical parameter for the output filter. In one example, the controller calculates a target current for inductor 21, while in another example, the controller calculates a target voltage for capacitor 23. The controller may calculate the required change in the electrical parameter based on the measured quantity (e.g. voltage or current) at the output filter. The controller may calculate a change value based on a difference between the target output level and the current measured quantity (□). The controller may compare the change value to the available output segments from the combination of components and select the closest combination.

Time of day	A-B	B-C	C-A	B-A	C-B	A-C	Target
								1	49	163	-212	-49	-163	212	110
2	-80	-135	215	80	135	-215	168
								3	-197	173	24	197	-173	-24	18
4	201	-25	-176	-201	25	176	-150
								5	-94	230	-136	94	-230	136	-170
6	196	-189	-7	-196	189	7	-75

TABLE 1

Different switch combinations correspond to different output ranges. For example, at time interval 3 in Table 1, combination C-A provides 24V, which is closest to the target (18) at time interval 3. In another example, at time interval 2, the combination C-B provides 135, which is closest to the target at time interval 2 (168). For each time interval, the controller selects one of the possible combinations. Only six combinations are shown, but more combinations are possible. A look-up table based on monophasic measurements may be used. Alternatively, the various phases may be measured and compared. The controller may compare the possible combinations to the target values and select the closest combination. The controller generates an excitation current control signal for the selected combination. The controller may output individual control signals for each of the switches SW 1-SW 6. Each of the switches SW 1-SW 6 may be on or off. Each combination represents a different current path through the segmented waveform converter. One or more combinations may be used to start the engine. One or more of these combinations may be used to start the engine with reverse power flow through the segmented waveform converter.

As another example, the controller may select a switching combination that provides a maximum voltage to the output and determine a Pulse Width Modulation (PWM) duty cycle to operate between the switching combination and the idle state. The PWM duty cycle may be selected based on a ratio between the target voltage and the available voltage, a predetermined sequence, a closed-loop output voltage controller, model-based control of the output, or similar techniques.

The controller may determine whether the closest available combination is within a threshold difference of the target. The controller may apply PWM control to adjust the signals when the nearest available combination is further from the target than the threshold. For example, the PWM duty cycle may be applied to the closest combination to approach the target. In another example, the controller first selects an available combination larger than the target when the closest available combination is further away from the target than the threshold. The controller then applies the PWM duty cycles to adjust the selected combination to approach the target. The PWM duty cycle may be calculated according to equation 1.

PWM duty cycle-target/selected combination output equation 1

For example, considering the example at time interval 2, the combination C-B provides 135, which is closest to the target at time interval 2 (168). The controller may return from combination (C-a) to the next maximum output (215). Using equation 1, the PWM duty cycle is (168/215) ═ 0.78 or 78%. In one example, the PWM duty cycle may be fine-tuned (e.g., every 1%). In another example, some examples may be used, and the closest PWM duty cycle is selected. For example, when five duty cycles are available, the options may be 20%, 40%, 60%, 80%, and 100%. In the example above, when equation 1 provides 78%, a PWM duty cycle of 80% is selected.

Table 2 shows exemplary control signals for each switch so that segmented waveform converter 20 provides various output levels or combinations of components of a multi-phase signal. The controller may include an output pin for each switch to provide a respective control signal to the switch. In another example, segmented waveform converter 20 may include a switch controller that receives the bitwise signal according to each row of table 2. For example, a series of bits correspond to a set of control signals in the form { SW1, SW2, SW3, SW4, SW5, SW6 }.

	SW1	SW2	SW3	SW4	SW5	SW6
							A-B	1	0	0	0	1	0
A-C	1	0	0	0	0	1
							B-C	0	1	0	0	0	1
B-A	0	1	0	1	0	0
							C-B	0	0	1	0	1	0
C-A	0	0	1	1	0	0
							0 or A-A	1	0	0	1	0	0
0 or B-B	0	1	0	0	1	0
							0 or C-C	0	0	1	0	0	1

TABLE 2

The controller may calculate a target electrical parameter of the output filter. In one example, the controller calculates a target current for inductor 21, while in another example, the controller calculates a target voltage for capacitor 23. The controller may calculate the required change in the electrical parameter based on the measured quantity (e.g. voltage or current) at the output filter. The controller calculates a variation value based on a difference between the target output level and the measured quantity (□). The controller compares the change value to the available output segments from the combination of components and selects the closest combination.

The filter component inductor 21 and capacitor 23 may be selected to minimize total harmonic distortion on the output of the inverter. The inductor 21 and the capacitor 23 may also be selected based on a target switching frequency of the segmented waveform converter. The filter components may be replaceable or may not be designed as small. The filter components may be different based on the target output voltage and frequency of the inverter. As one example, inductor 21 may decrease in size as the output frequency increases. As another example, the capacitor may increase in size due to the lower voltage application. The filter components may vary depending on the application, for example the filter size decreases when feeding a motor load, or the filter size increases when feeding a sensitive load.

The filter component may also cause the inverter to control the short circuit current by limiting the rate at which the current through the switch may rise. The current control may provide a sine wave, a trapezoidal wave, a sawtooth wave, a triangular wave, a DC wave, a square wave, or otherwise shape the output current as a short circuit. The frequency at which the output current becomes a short circuit may vary due to the nominal frequency. The current control may slowly decrease the output current of the high level to the output current of the lower level. As one example, the current control may provide 300% of the generator rated current into the short circuit within 2 seconds and then reduce the output current to 100% of the rated current in the next 5 seconds. As another example, the current control may provide 300% of the generator rated current into the short circuit within 5 seconds and then stop the output current.

Fig. 3A shows exemplary switches SW 1-SW 6 of the segmented waveform converter 20. Switches SW 1-SW 6 include a pair of transistors 25 (e.g., metal oxide semiconductor field effect transistors or MOSFETs), with transistor 25 being controlled by gate driver 27 through one or more gate resistors 26. The source of transistor 25 may be directly electrically connected. The switch may also utilize multiple transistors connected in parallel to increase the current rating or reduce the losses of the power conversion.

The switch is configured such that current is prevented from flowing in either direction. This allows the segmented waveform converter to switch between two AC waveforms. The body diode (if present) on each transistor may be turned on when the transistor is turned on in one direction, so the voltage drop across one transistor is typically lower than would otherwise be the case. The gate driver circuit provides the necessary isolation to allow the source of the switch to float with respect to the input and output of the converter, while providing the voltage or current referenced by the source to trigger the switch. The gate driver transmits the digital signal from the controller to the actual switch.

Fig. 3B shows further exemplary switches SW 1-SW 6 of the segmented waveform converter 20. Switches SW 1-SW 6 include a pair of transistors 29 (e.g., Insulated Gate Bipolar Transistors (IGBTs) or other three terminal power semiconductor devices). The emitters of the transistors 29 may be directly electrically connected. The switch may also utilize multiple transistors connected in parallel to increase the current rating or reduce the losses of the power conversion. If the thermal characteristics of the IGBTs are not conducive to parallel connection, a parallel resistor may be used to connect the emitters.

The switch is configured such that current is prevented from flowing in either direction. This allows the segmented waveform converter to switch between two AC waveforms. The body diode on each transistor may be turned on when the transistor is turned on in one direction, so the voltage drop across one transistor is typically lower than would otherwise be the case. The gate driver circuit provides the necessary isolation to allow the emitter of the switch to float with respect to the input and output of the converter, while providing the voltage or current referenced by the emitter to trigger the switch. The gate driver transmits the digital signal from the controller to the actual switch.

Fig. 4 shows an exemplary network 30a of segmented waveform converters. The inputs to the network 30a include: s1, S2, and S3 for the first segmented waveform converter; t1, T2, and T3 for the second segmented waveform converter; and U1, U2, and U3 for the third segmented waveform converter. The output of the network 30 includes an output line (L1, L2, L3) for each segmented waveform converter. The energy storage device 33 (which may be an inductor) is combined with the energy storage device 34 (which may be a capacitor) to form an output filter. A measurement point 37 for current and a measurement point 39 for voltage show exemplary locations on the network 30 where electrical quantities can be measured for controlling the segmented waveform converter. Other voltage and current measurement locations may also be used. The circuit 35 comprises an excitation current power supply for generating an excitation current (DC +, DC-) which is transmitted back to the excitation coil of the alternator.

In fig. 4, the respective segmented wave transformers share a neutral connection (N). Thus, each of L1 and L2 and L3 are connected only in parallel or in a three-phase wye configuration. Fig. 5 illustrates another exemplary three-phase segmented waveform converter, where each segmented waveform converter is independent and can be connected in any configuration.

Each converter is capable of providing a single phase AC output, but the phase between the outputs may be fixed, such that the converter network produces a multi-phase AC output. For example, the outputs of the three converters between 1 and 4, between 2 and 5, and between 3 and 6 may be fixed at 120 electrical degrees apart, providing three-phase power. As another example, outputs between 1 and 4, between 2 and 5, and between 3 and 6 may all produce voltages having the same phase angle, connecting them in parallel to provide increased current source capacity in single phase applications. In yet another example, one of the three outputs, i.e., 3 and 6, may produce a voltage having a 180 electrical degree difference from the other two outputs, i.e., 1 and 4 and 2 and 5, resulting in a center-tapped single-phase output voltage of, for example, 120/240. In this case, since the two converters are connected in parallel, the rated current of one of the output lines from the generator is twice the rated current of the other output line. In another example, outputs 1 and 4 may be 180 electrical degrees out of phase with 2 and 5 and 3 and 6 having the same phase angle, with 1 and 4 having twice the magnitude. This allows the center-tapped single phase output to have a voltage that balances the line current rating, but only half the line current from the neutral connection. This final configuration may require high voltage switches for the converter 31 connected to the inputs U1, U2, U3.

Fig. 6A illustrates an exemplary pin diagram for a circuit package or integrated circuit for a network of segmented waveform converters 30 a. Inputs S1, S2, S3, U1, U2, U3, T1, T2 and T3 of network 30a are all on one side of the circuit package, while line outputs L1, L2 and L3, neutral line N and field current outputs DC +, DC-are all on the other side of the circuit package. A Controller Area Network (CAN) provides control inputs to the circuit package to set the outputs. The control inputs may be the bitwise switch settings described above (e.g., { SW1, SW2, SW3, SW4, SW5, SW6}), or the control inputs may be target outputs, and the switch settings are controlled within the circuit package.

Fig. 6B shows an exemplary pin diagram of a similar circuit package or integrated circuit for the network of segmented waveform converters 30B. Inputs S1, S2, S3, U1, U2, U3, T1, T2, and T3 of network 30b are all on one side of the circuit package, while differential outputs 1, 2, 3, 4, 5, and 6 and field current outputs F +, F-are all on the other side of the circuit package. As described above, the CAN control input of the circuit package sets the output using the bitwise switch setting or target output level.

Fig. 6C shows an exemplary power supply 40 for controlling the field current. The field current supply 40 may be used in combination with the circuit of fig. 5 or in place of the circuit 35 of fig. 4. The power supply 40 comprises a transistor array 41 and a switching power supply for boosting.

The waveform converter network provides an output to control the field on the alternator 13, thereby causing the converter to control the supply voltage. The field on the alternator 13 may be supplied by a high voltage DC bus, generated from the battery voltage by a DC-DC converter. Control of the supply voltage may allow for improved efficiency, reduced stress of components, a wider output voltage range, and improved control under short circuit conditions, among other benefits.

In any of the above examples, the synchronous inverter may be connected to provide two equally rated (e.g., 120V) power sources, or the synchronous inverter may be connected in various configurations. The inverters communicate via a synchronization signal therebetween to cause the inverters to provide synchronized output voltages. In this case, the two inverters provide a very versatile range of output voltages, allowing a single generator package to be used in a variety of applications.

Fig. 7A and 7B show exemplary single-phase wiring diagrams for a synchronous inverter, which may be implemented by the segmented waveform converter of fig. 4 or 5. Fig. 7A shows a circuit as a means for connecting a low voltage (e.g., 120VAC) single phase output. Fig. 7B shows the circuit as one means for connecting the nominal voltage of a single phase configuration (e.g., 220 or 240 VAC).

Fig. 8A shows a circuit as a means for connecting a low-wye (e.g., 120/208VAC) three-phase configuration, which may be implemented by the segmented waveform converter of fig. 4 or 5. Fig. 8B shows a circuit as a means for connecting a high-wye (e.g., 230/400 or 277/480VAC) three-phase configuration, which may be implemented by the segmented waveform converter of fig. 5. Fig. 9 shows a circuit as a means for connecting a center tap □ (e.g., 120/240/208VAC) three-phase configuration, which may be implemented by the segmented waveform converter of fig. 5.

Fig. 10 shows an exemplary engine-generator set including an engine 51, a battery 52, a Controlled Field Machine (CFM)55, two segmented waveform converters 53, and a generator controller 50. Each segmented waveform converter 53 includes a power stage 54, a microprocessor 56 and a start switch 58. The microprocessor and/or start switch 58 may be referred to as a battery circuit and may be electrically connected to the battery 52 and configured to provide a digital start signal to the engine associated with the controlled field alternator. The engine 51 includes or is electrically connected to an Engine Control Module (ECM)57 and a crank angle sensor 59. The power stage 54 includes: a switch array for receiving CFM output 61 fed to segmented waveform converter 53; and an excitation current line 63 for supplying excitation current back to the CFM 55. The CFM 55 may be an alternator or another rotating device controlled by an electric field. Additionally, different or fewer components may be included in the genset.

The synchronous inverter 53 may be used to initiate engine rotation (start the engine 51). The synchronous inverter 53 receives battery power from the battery 52 at the normal AC output and provides an AC voltage waveform to the alternator stator windings, thereby generating a rotating magnetic flux of the stator. The rotating magnetic flux on the stator may generate a torque on the rotor. The torque generated will rotate the engine, causing air and fuel to be compressed in the cylinders and enabling the engine to initiate combustion (cranking).

The switches allow bi-directional power flow based on the topology of the segmented waveform converter. Given this configuration, a signal may be provided that allows the alternator to act as a motor to rotate the engine. The generator may be used as an inductor using damped windings in the rotor, induced currents in the rotor field windings, reluctance variations between the rotor and stator, magnetic hysteresis in the rotor, or eddy currents generated in the rotor steel or laminations. The generator may also be used as a synchronous machine by exciting the rotor field, by rectifying the induced voltage in the rotor field, or by providing a permanent magnet rotor. The rotor field may be excited by an AC voltage, a DC voltage, or a combination of AC and DC voltages. When the rotor is stationary, the rotor field supply may be coupled through the exciter armature.

The generator controller 50 may generate a start signal to start an engine associated with the controlled field alternator. The generator controller 50 is configured to provide a start signal to the segmented waveform converter 53. In addition to the start signal, the segmented waveform converter 53 may receive a relative to stationary component position signal of the rotating component to determine the speed and position of the engine. In some cases, the position signal may provide information to the segmented waveform converter 53 that allows for synchronizing the AC voltage applied to the stator of the alternator. The segmented waveform transformer may also determine the position of the motor by measuring the return electromagnetic field (EMF) from the stator windings, the stator impedance, the stator current, or another signal. In some cases, (the angle of) the output of the crank angle sensor 59 may be directly fed to the synchronous inverter 53. In other cases, information may be read by the ECM 57 or the generator controller 50 crank angle sensor 59 and communicated to the synchronous inverter 53.

The engine start may be performed by one or more of the segmented waveform converters. The converter may share the start-up load simultaneously, by occasionally switching the converter, or some combination of the two techniques. The converter for supplying current may be selected based on the temperature of each converter, the time the converter has supplied the starting current, in order to evaluate the functionality of the components on each converter, or for other reasons.

The engine start may also be performed by a separate converter or a three-phase inverter. The individual inverters may be part of a segmented waveform converter or individual converters. The individual converters may be connected to a dedicated set of windings on the alternator. The set of dedicated windings on the alternator may be electrically isolated from the windings connected to the segmented waveform converter. The set of dedicated windings may have a different number of turns than the main winding. The set of dedicated windings may be used to charge a battery that supplies the starting current.

Engine starting may be performed by controlling the frequency and magnitude of the applied voltage. The engine start may be performed by controlling the voltage and phase angle between the rotor and the stator. The engine start may be performed by controlling the torque applied to the engine 51. The torque applied to the motor may be measured in terms of the phase angle between the current and voltage, the magnitude of the current, the magnitude of the voltage, the speed of the motor, or other characteristics of the stator or rotor.

FIG. 11A shows a graph of total engine torque for an exemplary engine-generator set including a synchronous inverter. As shown in graph 110, for most engine operating speeds, the engine provides torque that increases with increasing speed. It may be difficult to quickly accelerate the engine from a lower speed due to the torque output limitations of the engine. Additionally, acceleration from a lower speed may take longer due to the infrequentness of the combustion events.

The engine torque produced may be significantly less than the engine torque shown in fig. 11A, depending on the torque requested by the alternator. The engine output torque may be controlled by controlling the fuel supplied to the engine. The engine output torque may be controlled by controlling the air supplied to the engine. The torque required by the alternator may increase as the electrical load increases. If the alternator torque exceeds the generated engine torque, the engine speed may be reduced. If the engine torque exceeds the alternator torque, the engine speed may increase. It may be desirable to limit the alternator torque to a level slightly below the engine torque in order to accelerate the engine.

FIG. 11B illustrates a graph of engine power with respect to an exemplary engine-generator set including a synchronous inverter. As shown in graph 112, the engine speed may be increased to provide sufficient power to meet the load demand. The engine speed may be controlled by controlling the torque output of the engine. To increase the engine speed, the synchronous inverter may need to temporarily lower the output voltage. If the engine is unable to provide sufficient power to supply the load, the inverter may need to temporarily step down the output voltage.

The engine may be operated at a fixed speed, with the output voltage being controlled by adjusting the field current. The engine may be operated at a variable speed, wherein the output voltage is controlled by adjusting the engine speed. The engine may be operated at a combination of fixed and variable speeds, with the output voltage being controlled by a combination of adjusting the speed and adjusting the field current. The output frequency of the alternator may be controlled by adjusting the engine speed. The synchronous inverter may increase the frequency of the output voltage in accordance with the output frequency of the alternator. The synchronous inverter may reduce the frequency of the output voltage in accordance with the output frequency of the alternator. Different alternator and engine types require different means of controlling the input voltage of the synchronous inverter.

The synchronous inverter may control the output from the alternator in order to control the input voltage of the segmented waveform converter. Control of the alternator output can provide improved protection for switches in the converter, reduced total harmonic distortion at the output, improved efficiency, better durability, and improved response.

Fig. 12A shows a graph 114 relating rotor losses and stator losses in an alternator on an exemplary engine-generator set including a synchronous inverter. The exemplary design uses a wound field alternator to generate the voltage supplied to the synchronous inverter and ECM that enables the engine speed to be regulated. Rotor losses in the alternator may be greatest at low speeds because the alternator operates at low speed saturation to achieve maximum voltage generation at minimum speeds. Stator losses may increase due to increased copper losses due to increased load and thus increased current. The total loss may be greatest at no load, since system efficiency is not important at no load. System losses may be minimal at 30% load, as 30% load is the most common operating point for the generator.

Fig. 12B shows a graph 116 of total system losses for an exemplary engine-generator set, where the total system losses include losses from the synchronous inverter. An exemplary generator set may be rated to produce 10 kW. The total system losses can be approximated by the sum of the alternator losses and the inverter losses. The overall efficiency may be calculated as the ratio between the total power provided by the alternator and the total power produced by the engine. The efficiency of an exemplary generator set may approach 90%.

As shown in fig. 12B, the engine speed increases as the generator load increases. This may enable the engine to provide sufficient power to supply the load, and may also improve fuel consumption, sound and air pollutant emissions, and system life. The engine speed may be held constant, decreased, or increased in different examples. The alternator voltage produced by the system may increase, remain constant, or decrease as the load increases. Increasing generator voltage with increasing load may help reduce total harmonic distortion; the voltage does not change with the change of the load, so that the control of the inverter can be simplified; and the voltage decreases as the load increases may help to reduce stress on components in the segmented waveform converter.

Fig. 13 illustrates an exemplary dual-shaft winding field alternator for providing voltage to a synchronous inverter. The exemplary alternator is configured with an exciter field that is co-planar with the main machine. The exemplary generator topology may provide additional voltage control and improved speed range over permanent magnet alternatives. The exemplary alternator topology may provide similar size distribution and efficiency to the permanent magnet alternative. The exemplary alternator topology may be integrated with the flywheel of the engine. In this example, the output shaft of the engine may drive a coolant pump, a fan, a fuel pump, another device, or may be removed from the shaft casting. The output seal may also be removed from the end plate casting of the engine.

Fig. 13 shows a shaft 222 supporting a rotor frame 223. The stator frame 221 is supported by a stationary member that provides a reference frame for the rotating rotor. The stationary member may be an engine block or a brake or other stationary member. The rotor frame 223 rotates with the shaft. The rotor frame 223 supports the rotor field assembly and exciter armature assembly 224 d. Thus, the rotor field assembly 224a and the exciter armature assembly 224d may be rigidly mounted together or integrally formed. The stator frame 221 supports an exciter field device 224c and a main stator device 224 b. Thus, the exciter field devices 224c and the main stator devices 224b are rigidly mounted in the same frame of reference relative to the rotor or may be integrally formed. One or both of the stator side and the rotor side may be formed of cast iron or steel or laminated silicon steel or other magnetically permeable material. The outermost component may be designed to act as a shield for electromagnetic interference due to high frequency switching of one or more power electronic devices inside the outermost component. Furthermore, the outermost components may be designed to minimize radiated electromagnetic interference conducted from external power electronics, such as a synchronous inverter, to the alternator.

An exciter air gap 225a is maintained between the exciter field assembly 224c and the exciter armature assembly 224 d. The exciter field assembly 224c is energized by a voltage regulator or another power source to generate an exciter field in the exciter air gap 225 a. The exciter armature assembly 224d is configured to rotate relative to the exciter field assembly 224c and imparts a first varying voltage across the exciter air gap 225a in a set of coils in the exciter armature. In one alternative, exciter field device 224c may include permanent magnets. In another alternative, the exciter field apparatus may comprise a coil or another magnetic field generating device.

A primary air gap 225b is maintained between the rotor field means 224a and the primary stator means 224 b. The main stator arrangement 224b includes a second set of coils. The rotor field arrangement 224a is configured to be energized by a first current in a first set of coils and the rotor field arrangement 224a generates a primary magnetic field that can impart a second varying voltage in the coils of the main stator arrangement 224b across the main air gap 225 b.

As shown in fig. 13, the main stator device 224b and exciter field device 224c lie in a common plane that is orthogonal to the axis of rotation of the shaft 222. In the first embodiment, only the main stator assembly 224b and the exciter field assembly 224c are located on a common plane with the rotor field assembly 224a and the exciter armature assembly 224d located on adjacent planes. In this example, adjacent planes including the rotor field device 224a and the exciter armature device 224d are spaced in the axial direction from the main stator device 224b and the exciter field device 224 c. In this embodiment, main air gap 225b and exciter air gap 225a are located on adjacent planes or a common plane orthogonal to the axis. In this first embodiment, the flux travels parallel to the axis of shaft rotation through the entire main air gap 225b and exciter air gap 225 a. In another embodiment, the main stator assembly 224b, the exciter field assembly 224c, the rotor field assembly 224a, and the exciter armature assembly 224d are located in a common plane. In this embodiment, main air gap 225b and exciter air gap 225a may be concentrically aligned parallel to the axis of shaft 222, with all or part of the cylindrical exciter air gap 225a contained within the cylindrical main air gap 225 b. Exciter armature assembly 224d is spaced inwardly from exciter field assembly 224c, main stator assembly 224b, and rotor field assembly 224 a. In other words, exciter machine armature assembly 224d is closer to shaft 222 than exciter field assembly 224c, main stator assembly 224b, and rotor assembly 224 a. In this second embodiment, the flux travels orthogonal to the axis of shaft rotation through the entire main air gap 225b and exciter air gap 225 a. Note that a combination of the first embodiment and the second embodiment is also possible and contemplated.

Fig. 14 illustrates an exemplary block diagram of an exemplary synchronous inverter system. The exemplary synchronous inverter includes three segmented waveform converters 205a, 205b, and 205c that can provide a potential to generate three-phase output power through filter circuits 207a, 207b, and 207 c. The controlled voltages S1, S2, S3, T1, T2, T3, U1, U2, and U3 from the alternator 13 may be supplied to the segmented waveform converters 205a, 205b, and 205c through the input filters 201a, 201b, and 201 c. The input voltages S1, S2, S3, T1, T2, T3, U1, U2, and U3 may be adjusted using the field current control device 216. The excitation current control device 216 may be a circuit or device configured to receive a command or control signal from the microcontroller 200 and generate an excitation current in response to the command. A control signal or command for field current control 216 may be generated by microcontroller 200. The segmented waveform converter may be controlled according to input metrics 203a, 203b, and 203c and output metrics 209a, 209b, and 209 c. The segmented waveform converter may be controlled by microcontroller 200.

The starting battery voltage may be applied to the segmented waveform converters 205a to 205c by switching the output contactors 202a to 202c and through the filters 207a to 207 c. The synchronous inverter may use segmented waveform converters 205 a-205 c to provide three-phase AC voltage across the generator windings to provide engine starting capability. Voltages S1, S2 and S3, T1, T2 and T3, and U1, U2 and U3 may be electrically isolated from each other. The voltages S1, S2 and S3, T1, T2 and T3 and U1, U2 and U3 may be connected to separate windings in the alternator 13.

The starting battery 218 may be charged from the alternator 13 from the inputs C1, C2, and C3. The voltages generated at C1, C2, and C3 may be electrically isolated from the voltages generated at S1, S2, S3, T1, T2, T3, U1, U2, and U3. The voltages supplied to C1, C2, and C3 may be generated by separate windings in the alternator 13. The battery charger 213 may receive the rectified DC voltage from C1, C2, and C3 through the rectifier 211. The battery charger 213 may be controlled based on a fixed sequence. The fixed battery charging sequence may include: a bulk charge mode in which the voltage is held at a higher level until the current drops below a threshold; a floating mode in which the voltage is maintained at a sufficiently low level to avoid overcharging the battery; and a balanced mode, in which the voltage is increased for a short duration to ensure that the charge in all cells in the battery is equal. The battery charger 213 may be controlled based on the battery gauge 215. The battery charger 213 may be controlled by the microcontroller 200. The microcontroller 200 may be powered by an onboard power supply 217. All components on the synchronous inverter may be switched at the same frequency to reduce electromagnetic interference (EMI) due to aliasing of signals.

The input filters 210 a-210 c may provide protection for the switches in the segmented waveform converters 205 a-205 c in addition to providing buffer circuits to the switches. Further, the input filter sections 201a to 201c may provide a bypass path for the current flowing through the inductance of the output winding supply S1, S2, S3, T1, T2, T3, U1, U2, and U3, thereby enabling switching of the current as needed to minimize harmonic distortion of the output voltage.

The output filters 207a to 207c may provide a bypass for high frequency switching noise from the segmented waveform converters 205a to 205 c. The microcontroller 200 can use the output metrics 209a, 209b, and 209c to determine the voltage on the output and the current in the filter inductor. Microcontroller 200 can determine the output current from the inverter based on the filter inductor current, the voltage on the filter capacitor, the switching position, past information from various signals, and system parameters such as the capacitance of the filter capacitor and the inductance of the filter inductor. Microcontroller 200 can determine the capacitance value of the filter capacitor over time. The inductance of the filter inductor over time can be known to the microcontroller 200. The output metrics 209a, 209b, and 209c may include measurements of the output current.

The microcontroller 200 can determine the active and reactive droop characteristics based on the calculated or measured output current from each inverter. The active and reactive droop characteristics can be used to operate seamlessly in parallel with a standard generator. The active and reactive droop characteristics may allow the use of a synchronous inverter to operate in parallel with another generator. The output of the generator may be protected outside the four quadrant capability curve of the generator by opening all switches, closing all switches, some combination thereof, or by some other function controlled by the microcontroller.

Fig. 15 illustrates an exemplary synchronous inverter topology that places the segmented waveform converters on C1, C2, and C3 to start the engine. This example is similar to the example shown in fig. 14, except that: a fourth segmented waveform transformer 205d is added; and corresponding input filter 201d, input meter 203d, output filter 207d, and output meter 209 d; and the output contacts 202 a-202 c are removed. If flux is applied to the stator without exciting the rotor field, the additional segmented waveform converter 205d may provide the ability to derive an AC output voltage from the generator without the motor running. The magnetic flux applied to the stator by the windings C1, C2, and C3 may generate voltages S1, S2, S3, T1, T2, T3, U1, U2, and U3 across the windings of the alternator 13. This capability may require different alternator topologies, such as the ability to disconnect the rotor field from the exciter armature or rectifier and remove any damper or induction windings in the rotor.

The synchronous inverter may start the engine when the starting battery voltage is applied to the segmented waveform converters 205a to 205 c. The start sequence may be initiated by a digital signal, a communication signal, the status of existing inputs and outputs, or by the presence of a start battery voltage on the output as detected by the output meters 209a, 209b, and 209C. The activation may be controlled by microcontroller 200. As an example, the microcontroller may provide a start signal (e.g., a digital start signal) to an engine associated with the controlled field alternator. The start-up may be performed by measuring the phase angle of the alternator rotor and moving the magnetic flux to a position at a given angle to the rotor position. The start can be controlled by measuring the speed of the alternator rotor and rotating the magnetic flux with a given speed difference, also referred to as slip frequency. The start may be controlled by providing a fixed rotational frequency in a known direction without feedback from the engine.

Combining control of input voltage and frequency within the same synchronous inverter that can provide output voltage and frequency can provide various advantages. As one example, a synchronous inverter may provide 139VAC line-to-neutral voltage to produce a low wye configuration of 240VAC line-to-line voltage or a high wye configuration of 480VAC line-to-line voltage. Providing this additional voltage may require increasing the input voltage from the generator, but may not require increasing such voltage when providing a 120VAC line to neutral to produce a 208VAC line to line voltage. Including control of engine speed, may enable the synchronous inverter to improve the efficiency of the system by minimizing engine speed, or by providing a frequency that is an integer multiple or simple ratio of the desired output frequency. Further, control of the engine speed may enable the synchronous inverter to regulate voltages outside of the range of voltages provided by regulating the field current. As one example, an alternator may only be capable of generating 90VAC at 1000RPM, but may require 100VAC to generate 139VAC line-to-neutral voltage. In this case, the synchronous inverter may increase the engine speed to 1100RPM in order to provide 100 VAC.

The alternator field current may be provided by a battery, the AC output of the generator, a dedicated coil on the alternator, or a combination of various sources. Synchronous inverters may use half-bridge or full-bridge power supplies to control the excitation current. The half-bridge power supply may be capable of providing a positive voltage to the field and allowing the positive voltage to decay naturally. The full bridge power supply may be capable of providing negative and positive voltages to the field, thereby increasing and decreasing current more rapidly. The half-bridge driver may be supplied with a battery voltage or a higher voltage generated from a battery voltage or other source. The full bridge driver may be supplied with a battery voltage or a higher voltage generated from a battery voltage or other source.

Incorporating engine starting capability into the synchronous inverter may allow for a reduction in overall system complexity by utilizing the same components for both operations and eliminating the need for separate starter motors. Using an alternator for starting, it is possible to achieve: a quieter starting operation is provided due to the removal of the electrical power delivered through the spur gears on the starter motor and on the flywheel; the current consumption on the starting battery is reduced by the improved efficiency; reduced wear on the system due to minimal side loading at start-up; higher starting speed due to lower loss connections; reduced package size and lower cost due to the elimination of a dedicated starter motor; and electrical isolation due to the use of a winding in the alternator separate from the battery charging winding.

Integrating battery charging in the inverter can reduce overall package size by eliminating the battery charging alternator; improving system reliability by removing the drive mechanism for the battery charging alternator; reducing system complexity by eliminating a controller; providing electrical isolation between the battery and the generator output by using separate windings; and providing high voltage power for the field from the battery charge winding.

The alternator 13 may have an inductance in the stator that may cause voltage spikes on the input to the segmented waveform converter. The voltage spikes generated by the inductance can be minimized by the input filter, by the control algorithm for the segmented waveform converter, and by control of the alternator field and engine speed.

The output of the synchronous inverter can be used to operate the motor, similar to variable frequency drive operation. The segmented waveform converter topology may allow for bidirectional power transfer from the motor, allowing for interruption of regeneration from the motor. If multiple motors are being driven by a given generator, power may be delivered to each other among the multiple motors.

The alternator may have characteristics that vary slightly with temperature and manufacturing tolerance stack-ups. The microcontroller in the inverter can utilize a synchronous inverter configuration to adapt to changing characteristics to allow consistent operation across all products. The performance characteristics of the engine may also vary with atmospheric conditions, manufacturing tolerances, fuel type, and maintenance items. The microcontroller may be able to adapt the engine characteristics in order to provide a desired power quality over the entire load range.

The microcontroller 200 may use closed loop feedback from output metering to control the output voltage. The microcontroller 200 can control the output voltage according to the input voltage. The voltage may be controlled using a combined feedback and feedforward system with a feedforward table that may provide adaptive learning capabilities.

In a short circuit condition, microcontroller 200 may use closed loop feedback from output metering to control the output current. The output filter inductor may limit the rate of rise of the output current, potentially preventing the switch from being damaged when entering a short circuit condition. The short circuit current may be controlled by a switch in the segmented waveform converter, an excitation level in the alternator, or a combination of both. Further, the output current may be controlled with an inverter connected to the motor so as to limit the motor torque.

Where multiple inverters are used, the inverters may transmit synchronization signals to match the phase angles between the different inverters. The synchronization signal may be provided by transmitting a digital signal and an analog signal or by observing the input voltage from the alternator and other techniques. The synchronization signal may provide load information, target information, control mode, connection information, and the like. If multiple inverters are used, only one inverter can control the field current. That is, other inverters in the system may need to regulate their supply voltage, so the inverters may communicate the required input voltage through a communication network, digital signals, or analog signals.

If multiple inverters are used in parallel, the inverters may need to share load information in order to balance the load on the various inverters. This may be provided by transmitting a digital signal, an analog signal, or a simple droop process.

The output voltages from different inverters may be connected in parallel with other inverters, or even multiple output stages from a single inverter may be connected together. The configuration of the output of the inverter may be user adjustable, or the configuration may automatically detect that the outputs are connected together in order to determine how to control the voltage. Automatic connection detection may involve a specific power-up sequence in the case of one inverter stage observing the voltage on the input, may involve a current monitored for abnormal currents, may involve the transmission on the output of a special signal to be received by another device or by another technique.

Fig. 16 shows an exemplary generator controller 91. Generator controller 91 may include a processor 300, a memory 352, and a communication interface 353. The generator controller 91 may be connected to a workstation 359 or other external device (e.g., a control panel) and/or a database 357 to receive user input, system characteristics, and any values described herein. Optionally, the generator controller 91 may include an input device 355 and/or a sensing circuit 311. The sensing circuit 311 receives sensor measurements (e.g., alternator output SWC output) from those described above. In addition, different or fewer components may be included. The processor 300 is configured to execute instructions stored in the memory 352 for performing the algorithms described herein. The processor 300 may be compatible with various engine and alternator combinations and may identify an engine type, make, or model and may look up system features, settings, or profiles based on the identified engine type, make, or model. FIG. 17 is a flow chart of the operation of the generator controller of FIG. 16. In addition, different fewer acts may be included.

At action S101, the processor 300 accesses the measured amount of power at the inverter output from the memory 352 or from a real-time measurement (e.g., sensing circuit 311). The inverter output may be the actual power signal applied to the load under certain specifications. The specification may be a target value of a sinusoidal signal with a certain time interval. Alternatively, the target value may specify an amplitude range or a root mean square range of the inverter output. The target value may specify a variance or quality (e.g., total harmonic distortion) level of the inverter output.

At action S103, the processor 300 calculates a variation value based on the target value and the measured electric quantity. In other words, the processor 300 determines the difference between the target value and the actual value of the inverter output. The variation value may be a positive or negative number.

At action S105, the processor 300 compares the variance value with the available inverter inputs. A set of available inverter inputs is shown in each row of table 1 above. The available inverter input depends on the expected or actual value of the output of the alternator. For example, in a three-phase alternator having outputs A, B and C, the set of outputs may be A, B, C, A-B, B-C, A-C, B-A, C-B and C-A. Each output in the set of outputs has a value that varies at each time interval (e.g., sampling interval).

At action S107, the processor 300 selects the closest available inverter input combination (alternator output) based on the comparison. In one embodiment, the closest available inverter input combination is used without modification. In another embodiment, the closest available inverter input combination is modified to more closely achieve the target value using PWM.

At action S109, the processor determines the switch settings for the switch array of the segmented waveform converter corresponding to the selected inverter input combination. The switch settings are a digital signal or series of bits that describe which switches of the segmented waveform converter are to be turned on and off to provide a selected inverter input combination.

At action S111, the processor 300 provides a waveform corresponding to the switch setting to the inverter output. In one example, the processor 300 calculates a difference between the closest available inverter input combined to the target value and modifies the waveform using a pulse width modulated signal having a duty cycle based on the difference between the closest available inverter input and the target value.

The systems herein may be configured and/or capable of performing various methods. An exemplary method may include: generating a multi-phase signal at a controlled field alternator; determining an output control signal for a segmented waveform converter to control a plurality of switches connected between a polyphase signal of a controlled field alternator and an output filter, wherein the output control signal determines an output of the segmented waveform converter; and determining a field current control signal to control a field current of the controlled field alternator.

In some cases, the method may include: sending an output control signal to a load; and providing the field current control signal to the generator controller.

In some cases, the method may include: calculating a plurality of combinations of available voltages by different settings for the plurality of switches, wherein the excitation current control signal includes at least one of the plurality of combinations. In some of these cases, the method may further comprise: calculating a plurality of combinations of available voltages by different settings for the plurality of switches, wherein the excitation current control signal includes at least one of the plurality of combinations. In some of these cases, the method may further comprise: wherein the plurality of combinations represent different paths through the segmented waveform converter.

In some cases, the method may include: wherein a first combination of switches from the plurality of switches is associated with a first output range and a second combination of switches from the plurality of switches is associated with a second output range.

In some cases, the method may include: a start signal is generated to start an engine associated with the controlled field alternator.

Fig. 18 shows an exemplary system comprising an engine 401, an alternator 403, two synchronous inverters or segmented waveform converters 405a and 405b, an output device 400, and a battery 413. One of the synchronous inverters 405a is coupled with a motor 407a, a brake 409a, and wheels 411a, and the other synchronous inverter 405b is coupled with a motor 407b, a brake 409b, and wheels 411 b. One or both of motors 407a and 407b are examples of output drive mechanisms for the system. The motors 407a and 407b may function individually as motors 407 and interchangeably as motors 407, the brakes 409a and 409b may function individually as brakes 409 and interchangeably as brakes 409, and the wheels 411a and 411b may function individually as wheels 411 and interchangeably as wheels 411. The engine 401 may directly drive the output device 400. In addition, different or fewer components may be included.

The alternator 403 is mechanically coupled with the engine 401. As described in the previous embodiments, rotation of the output shaft of the engine 401 rotates the exciter section and the main field section of the alternator 403. The exciter portion includes an exciter armature for generating a field current to induce a time-varying magnetic flux in the armature windings to generate a voltage. The induced voltage in the windings of the exciter armature is connected to the main field part of the generator. The corresponding field current of the output of the exciter provides a magnetic field in the rotor field of the main field part of the generator. As the main field portion of the alternator rotates relative to the stator, magnetic flux passes through and across the alternator stator windings, thereby generating an alternator output signal in the bus bar 402. Alternatives to field control (e.g., brushes and slip rings, field weakening coils, direct axis current injection) are also included herein.

The output signal of the alternator may include a number of components that are selectively controlled by the synchronous inverters 405a and 405 b. May be performed by the generator controller 50, the generator controller 91, or the microcontroller 200 (any of which is individually referred to as "controller") in the examples described above: the derivation of the output of the synchronous inverters 405a and 405b, or the conversion of the alternator output signals to the output of the synchronous inverters 405a and 405 b. The controller may consult a look-up table or configuration values specific to a particular type of motor application for the motor, or feedback based on the current operation of the motor. The controller may determine switch settings for a plurality of settings that set the output of the synchronous inverter to a combination of the plurality of components of the alternator output signal. One of the components may be delivered, or multiple components may be added or subtracted. The controller may apply a switch setting to at least one segmented waveform transformer that includes a plurality of switches connected between the alternator 403 and the output drive mechanism (e.g., motors 407a and/or 407 b).

The motors 407a and 407b may be AC motors that include stationary stators including coils to which alternating current is supplied by synchronous inverters 405a and 405b (referred to individually or as synchronous inverters 405). The coil induces a rotating magnetic field that rotates a rotor attached to an output shaft of the AC motor. The stator and the rotor may be housed within a housing, and the stator may be mechanically coupled to the housing. The output shaft may be rotationally mounted to the housing using a bearing.

The output of the synchronous inverter 405 may include a drive frequency that rotates the output shaft of the motor at a particular speed. In one example, the output shaft rotational speed per second is the same as the drive frequency in cycles per second or the drive frequency related by a predetermined ratio. In other examples, the drive frequency and shaft speed may not be related by a predetermined ratio for an induction motor. The predetermined ratio may depend on the number of poles of the rotor and/or the number of poles of the stator.

The output of the synchronous inverter 405 may be selected via a switch setting such that the speed of the output shaft varies over time. The speed change of the output shaft may be within a time interval that is less than a single rotation of the output shaft or even less than the period of the output of the synchronous inverter 405, which may be referred to as electrical sub-cycle torque control. The electrical sub-cycle torque control applies a torque variation to the output shaft that is smaller than the electrical cycle of the output of the synchronous inverter 405. The electrical sub-cycle torque control may be on the order of 1 millisecond to tens of milliseconds. In this way, very rapid changes can be applied to the output shaft. The shaft may rotate at multiple speeds in only a few rotations or even a single rotation.

The controller may select the output of the synchronous inverter 405 based on a feedback signal, an input signal, or both, with respect to the rotation of the output shaft. The input signal may come from an input device for setting the speed of the rotor. The feedback signal may be generated by a sensor, such as a rotation sensor. The rotation sensor may measure rotation of the output shaft magnetically, optically or mechanically. Thus, the feedback signal may be indicative of the speed of the output shaft.

Further, a feedback signal may be derived from the output of the synchronous inverter 405. The controller may calculate a shaft output characteristic, such as speed or torque, from the output voltage or current of the synchronous inverter. The controller may compare the feedback signal to the input signal. When the input signal indicates that the speed or torque of the output shaft is greater than the speed or torque target, the controller reduces the frequency, voltage or current output of the synchronous inverter 405. Likewise, when the input signal indicates that the speed of the output shaft is less than the target, the controller increases the frequency, voltage or current output of the synchronous inverter 405.

By synchronizing the inverter 405, the speed of the engine 401 and alternator 403 can be independent of the frequency applied to the motor 407, and therefore independent of the speed of the wheels 411. Thus, it is possible to control only the engine 401 and the alternator 403 to optimize the output device 400 (e.g., the speed of the output device), and the synchronous inverter 405 controls the speed of the motor 407. Only the power or voltage output of the alternator 403 is controlled to adequately supply the synchronous inverter.

The speed of the engine 401 and the output of the synchronous inverter 405 may be independent within the operating range of the engine 401. With this operating range, the speed of the output device 400 can be adjusted without hindering the speed applied to the motor 407 and the wheels 411. In other words, when engine 401 is operating within a predetermined power range or rotational speed range, the speed of wheels 411 may be operating within any predetermined speed range in which the predetermined power range of engine 401 meets the power requirements.

The battery 413 is connected to the synchronous inverter 405 to serve as a power source and a power pool. The synchronous inverter 405 may be configured to charge the battery 413 or use the battery 413 as an electric power source to start the engine 401 via the alternator 403. The synchronous inverter 405 may also use the battery 413 to provide power to the motor 407 or to actuate the brakes 409 with limited capacity. The system is capable of transferring power between components without the use of a battery. The battery capacity may not be sufficient to provide full power to all components.

Power may also travel in the opposite direction, i.e., from the motor 407 to the synchronous inverter 405. For example, a reverse torque may be applied to the motor 407a, causing a reverse current to the alternator 403 through the synchronous inverter 405 a. Through power bus 402, the reverse current may facilitate power being drawn by synchronous inverter 405b and applied to motor 407 b.

In one example, the system shown in fig. 18 is applied to a vehicle, such as a forklift, loader, golf cart, or lawn mower, such as a zero turn radius lawn mower. The zero turning radius mower may be a mower in which at least two wheels are individually controlled. Although the term "lawn mower" may be used in some of the following embodiments, alternatives may be made for other types of vehicles. In addition to the application of the drive system and the synchronous inverter to deck and mower equipment, the drive system and the synchronous inverter may be applied to other types of vehicles. Thus, each wheel 411a and 411b is controlled by the output of the synchronous inverters 405a and 405b, respectively. The first segmented waveform converter 405a is associated with a first wheel 411a of the vehicle and the second segmented waveform converter 405b is associated with a second wheel 411b of the vehicle. The first wheel 411a and/or the second wheel 411b are coupled to a power train, which is an output drive mechanism (main drive system), to propel the vehicle. In alternative embodiments, only a single wheel is controlled, multiple wheels are connected to a single motor, or three or more motors for multiple wheels are controlled.

The advantage of using a synchronous waveform converter for electrical control can be achieved by hydraulic or other mechanical systems. For example, electric drives are more efficient than hydraulic systems, in addition to torque control of increased granularity. Efficiency in fuel costs can be selected to improve economy and smaller engines. Other advantages of electrical systems over hydraulic systems include the elimination of hydraulic oil leaks that may damage equipment or vegetation.

The lawn mower may also include a mowing system. A mowing system includes one or more blades configured to cut grass or other vegetation. The mowing system may correspond to the output device 400. A shaft, belt, or other drive train may mechanically connect the engine 401 to the output device 400. The output device 400 and motor 401 may respond to the power demand of the cut depending on the particular local requirements (e.g., thickness of vegetation, water content, or other factors).

In operation, the speed of the wheels is the same when the vehicle is generally traveling in a straight line. However, during cornering, the inner wheels experience a lower average speed or number of revolutions relative to the curve or turn than the outer wheels relative to the curve or turn. To slow the wheels to reduce the vehicle speed, the brake 409 may be applied to the wheels 411. Further, power transmission (e.g., negative torque, reverse torque, backward torque) can be performed from the inner wheel to the outer wheel. The kinetic energy of the rotating mass of the inner wheels is dissipated to deliver power to the outer wheels, thereby generating braking forces on the inner wheels, while accelerating forces are generated on the outer wheels, without the need for power to be drawn from or supplemented by the engine. As an example, the kinetic energy of the rotating mass of the inner wheel 411a is used to drive the motor 407a to generate electrical power, controlled by the synchronous inverter 405a, delivered to the synchronous inverter 405b via the bus 402 for driving the outer wheel 411 b. In another embodiment, the power delivered by the inner wheel synchronization inverter 405a may be used to charge the battery 413 or 505.

In one example, the controller is configured to generate a magnetic field control signal and provide the magnetic field control signal to the controlled field alternator 403. The field control may adjust the excitation current. Alternatively, the magnetic flux or field control signal may be modified using armature reaction techniques such as adjusting the current on the flux weakening coil or mechanical techniques such as changing the linkage path of the magnetic circuit. In other examples, a DC output from at least one of the segmented waveform converters may be applied to controlled field alternator 403 as an excitation current. The DC output may be generated by the circuit 35 described in other embodiments. The magnetic field control may be provided by one or more of the synchronous inverter DC outputs. Alternatively, the magnetic field control may be provided by another device with or without a signal from the synchronous inverter 405.

The DC output of the other synchronous inverters may be applied to the release mechanism for the brake 409. The primary function of the brake is to slow the wheels 411 when activated. However, the brake 409 may include a safety mechanism (e.g., a spring) that defaults to biasing the brake 409 to stop the vehicle. When the DC output of the synchronous inverter so signals, the safety mechanism may be released by an actuator (e.g., a solenoid valve). This may cause the brakes to be applied when the engine 401 or synchronous inverter is turned off, and may cause the brakes to be released when the engine 401 or synchronous inverter is running and applying the DC output.

The DC output of other synchronous inverters may be used for other purposes such as a control panel, safety mechanism, or status indicator. The control panel may include an interface for setting the output of the synchronous inverter. The safety mechanism may be a circuit for measuring the electrical quantity of the synchronous inverter, then comparing it with a threshold value, and in case the threshold value is exceeded, identifying an error. The status indicator may include one or more lights or displays that may indicate a synchronous inverter. In another embodiment, the DC output of other synchronous inverters may be used to power accessory outlets or lighting devices of a configurable AC or DC nature.

Fig. 19 shows an exemplary alternator and three synchronous inverters for a lawn mower. Similar components previously shown are consistent with fig. 19. In addition, different or fewer components may be included.

Fig. 19 includes a third synchronous inverter 405c for controlling a third motor 407c of a mower 410 (e.g., a mower deck). Thus, the output drive mechanism (auxiliary drive system) coupled to the synchronous inverter 405c drives the mower 410. In the present embodiment, the engine 401 drives only the alternator 403. The engine speed and torque may be controlled only for the total power demand of the system, which may be balanced and distributed by the synchronous inverter 405. In other words, the cutting speed of the mower 410 is independent of the engine speed, and the speed of each wheel 411 is independent of the engine speed. Also, the cutting speed of mower 410 may be independent of the speed of each wheel 411 (e.g., wheel 411a is independent of mower 410, wheel 411b is independent of mower 410, and wheel 411a is independent of wheel 411 b). In the embodiment of fig. 19, any of the DC outputs of the synchronous inverter 405 may supply field current to the alternator 403. In one example, the magnetic field control is provided by a synchronous inverter 405c for driving the mower 410.

Fig. 20 shows an exemplary lawn mower implementing a synchronous inverter for battery charging. The engine 401 in the embodiment of fig. 20 directly drives the mower 410. Similar components previously shown are consistent with fig. 20. In addition, different or fewer components may be included.

The synchronous inverter 503 (additional segmented waveform converter) may also be configured and operated by the controller and applies power from the battery 505 to the power bus 402 and correspondingly to the synchronous inverter 405 and the motor 407. Power may also flow in the opposite direction. That is, when braking or otherwise slowing one of the wheels 411, the motor 407 may act as a generator and provide power to the synchronous inverter 503 to charge the battery 505. Thus, either of synchronous inverters 405a and 405b may charge battery 505.

A switch 501, which may be implemented as a relay or an additional synchronous inverter, connects the alternator 403 to the power bus 402 and disconnects the alternator 403 from the power bus 402. The switch 501 may also be operated by the controller.

Power may be supplied to other electrical systems or mower accessories at accessory output 507 provided by synchronous inverter 503. Other accessories may include headlights, dashboards, turn signals, speakers, radios, or other devices.

Fig. 21 shows an exemplary lawn mower implementing three further synchronous inverters in addition to the synchronous inverter for battery charging. Similar components previously shown are consistent with fig. 21. In addition, different or fewer components may be included.

In the present embodiment, the synchronous inverter 405c supplies power to the motor 407c for driving the mower 410. Further, the DC output of the synchronous inverter 405c may set the height of the deck 610 of the mower 410. The controller may receive user input regarding deck height (e.g., distance from the ground) and, in response, control the switch settings of the synchronous inverter 405c to raise or lower the deck 610 using another motor or drive mechanism.

FIG. 22 illustrates an exemplary lawn mower implementing three synchronized inverters and a common source. Similar components previously shown are consistent with fig. 22. In addition, different or fewer components may be included.

The embodiment of fig. 22 includes a utility source that may also provide power to power bus 402 through synchronous inverters 613a and 613 b. Any number of synchronous inverters may be coupled to the common source 615. The utility source may be provided to the AC source of the mower by various delivery mechanisms. In one example, the electrical wiring may extend from a utility source (e.g., an electrical outlet) to the vehicle. Alternatively, an inductive coupling or other wireless coupling may provide the common source 615. For example, one or more induction coils may be buried or otherwise placed below the drive surface. The induction coils induce a voltage on one or more receiving coils in the mower and provide power to synchronous inverters 613a and 613b configured and operated by the controller.

Fig. 23 shows an exemplary mower implementing a synchronous inverter for driving movement of the mower, mowing the mower, and an additional synchronous inverter for charging the battery 505 and a common source 615. Similar components previously shown are consistent with fig. 23. In addition, different or fewer components may be included.

Depending on the circumstances or current settings, the utility source 615, battery 505, and/or alternator 403 may provide power to the wheels 411a and 411b through the synchronous inverters 405a and 405b and/or to the mower 410 and/or deck 610 through the synchronous inverter 405 c. Also depending on different circumstances or current settings, the utility source 615 and/or the alternator 403 may charge the battery 505 through the synchronous inverter 603.

FIG. 24 shows an example lawn mower and utility source, but without an engine. Similar components previously shown are consistent with fig. 24. In addition, different or fewer components may be included.

Depending on different circumstances or current settings, the utility source 615 and/or the battery 505 may provide power to the wheels 411a and 411b through the synchronous inverters 405a and 405b and/or to the mower 410 and/or the deck 610 through the synchronous inverter 405 c. Also depending on different circumstances or current settings, the utility source 615 may charge the battery 505 through the synchronous inverter 603.

The battery 505 may also provide power to an external device, such as a light tower. For example, at certain times, the utility source 615 charges the battery 505 when the utility source (e.g., induction coil) is nearby, and the battery 505 provides power to an external device when the mower is remote from the utility source 615.

FIG. 25 illustrates an exemplary vehicle including a synchronous inverter. Although two synchronous inverters 405 are shown, more or fewer synchronous inverters may be used to power the motor 707. In the case of more than one synchronous inverter 405, they will operate in parallel to increase capacitance, increase voltage, increase redundancy or improve controllability. Similar components previously shown are consistent with fig. 25. In addition, different or fewer components may be included. The embodiment of fig. 25 may be a different mower than a zero turning radius mower. The vehicle includes an engine 401, an alternator 403, one or more synchronous inverters 405a and 405b, a motor 707 coupled to wheels 711, a manual brake 703, an emergency brake 705, and an output 710. The wheels may be connected directly to the motor or via a torque converter (e.g., gear reduction, differential). The steering mechanism steers the wheels 711 in unison. As described in the previous embodiments, the power transmission may occur in the forward direction from the alternator 403 through the synchronous inverter 405 to the motor 707 and then finally to the wheels 711. The output of one of the synchronous inverters 405 may provide an output 710, where the output 710 may be converted from DC to AC (e.g., 120V for ease of output).

Fig. 26 shows an exemplary vehicle including a synchronous inverter other than the synchronous inverter for battery charging. Similar components previously shown are consistent with fig. 26. In addition, different or fewer components may be included.

As described in the previous embodiments, bidirectional power transfer may occur in the forward direction from alternator 403 through synchronous inverter 405 to motor 707, and in the reverse direction from wheels 711 through synchronous inverters 405 and 603a to battery 505 in response to emergency brake 705 or handbrake 703 being applied.

Unlike the manual brake in the embodiment of fig. 25, the brake 805 provides a stopping capability that is different from the stopping capability provided in the regenerative control scheme. In the regenerative mode, the motor 707 provides power to the generator 403, the battery 505, the output 710 or 507, or any combination thereof, through the synchronous inverter 405.

Fig. 27 shows an exemplary vehicle that includes a synchronous inverter and a utility source 615. Depending on different circumstances or current settings, utility source 615, battery 505, and/or alternator 403 may provide power to wheels 711 through synchronous inverters 405a and 405 b. Also depending on different circumstances or current settings, the utility source 615 and/or the alternator 403 may charge the battery 505 through the synchronous inverter 603.

Fig. 28 illustrates an exemplary generator system including a synchronous inverter system. Similar components previously shown are consistent with fig. 28. Output 710 is a DC output and output 721 is an AC output. By synchronizing the inverters 405a and 405b, the engine 401 can be operated at variable speeds while providing a constant AC output 721.

Fig. 29 shows an exemplary generator system including a synchronous inverter system that provides power from a generator in addition to a synchronous inverter that supplies power to a battery. Similar components previously shown are consistent with fig. 29. Each synchronous inverter system may provide a DC output. Synchronous inverters 603a and 603b provide a DC output 810b, and synchronous inverters 403a and 403b provide a DC output 810 a.

FIG. 30 illustrates another exemplary generator system having a synchronous inverter. Similar components previously shown are consistent with fig. 30.

The capacitor bank 823 may adapt single phase utility from the utility source 615 for the synchronous inverter. The capacitor bank 823 generates a multiphase signal from single phase utility by phase shifting a single phase source. The phase difference is used to provide a multi-phase input to the synchronous inverter 403. The capacitor bank 823 may include two or more capacitors, or two or more groups of capacitors, for converting a single phase source to a three phase signal. The single phase common source may be designated as phase a, the output of the first capacitor or set of capacitors may be designated as phase B, and the output of the second capacitor or set of capacitors may be designated as phase C.

Fig. 31 shows a flow chart of the operation of the generator controller of fig. 16. In addition, different fewer acts may be included.

At action S201, the processor 300 identifies a multi-phase signal at a controlled field alternator (e.g., alternator 403). The multi-phase signal may be detected by the sense circuit 311.

At action S203, the processor 300 determines output control signals for the at least one synchronous inverter to control switches connected between the multiphase signals of the controlled field alternator and the at least one output device. The output control signal determines an output of the at least one synchronous inverter.

At action S205, the processor 300 determines an output torque of at least one output device. The output device may be a wheel, a drive mechanism, a mowing system, a deck height system, or a generator. In alternative embodiments, the processor 300 may determine a speed, position, or other goal of outputting at least one output device. Further, a controlled field alternator may be used as a source of electrical power, or electrical power may be provided by alternative sources (e.g., utility, battery, wind, solar, nuclear).

Synchronous inverter circuit with output filter

Referring to fig. 14 and 15, one or more segmented waveform converters 205 include a plurality of switches connected to the multiphase signals of the controlled field alternator and are configured to generate three-phase output power through an output filter circuit, wherein the output filter circuit includes at least one output filter 207. The output power may be referred to as a drive signal, which may drive at least one motor, such as described in the examples of fig. 24-31. The segmented waveform input circuit may include an input filter 201 and include an input connected to the controlled field alternator configured to receive the multi-phase signal from the controlled field alternator. The at least one output filter 207 is configured to modify the drive signal based on at least one setting for the motor. The controller 200 is configured to generate a control signal for setting the switch state to generate a drive signal for the at least one motor. The control signal may be based on sensor data.

Referring to fig. 32A, an exemplary engine-generator assembly 70 includes the synchronous inverter 11, the engine 12, the generator 13, and an output filter 74, and is coupled to the load device 65. The synchronous inverter 11 may include: an input coupled to the controlled field alternator, the input configured to receive a multi-phase signal from the controlled field alternator; and at least one controller (i.e., microprocessor) for controlling the switching network of the segmented waveform converter connected to the multiphase signals of the alternator 13, and synchronizing the inverter 11 to generate drive signals for at least one load device 75. Further, the alternator 13 may be a controlled field alternator in which a generator controller (field current controller) actively controls the field current to regulate the output of the alternator 13.

The electrical noise from the alternator, in which the waveform deviates from the ideal sinusoid, becomes mechanical noise (audio) when the waveform powers the motor. In AC-AC converters, noise is generally not a design issue. For heavy equipment, such as mining equipment, mechanical noise from the electric motor may be acceptable relative to cost, as other noise in the environment tends to outweigh the noise of the electric motor. Other applications may require less noise to be generated by the electric motor. In some examples, the sound from hydraulics may exceed the sound of the engine. In some applications, such as a cart or mower used in quiet environments such as golf courses, sound becomes a priority. Output filter 74 reduces noise on the waveform output from alternator 12, which may include audible noise and electromagnetic interference. The output filter 74 may also reduce heating in the motor because the filtered waveform more closely matches the physical characteristics of the motor.

The output filter 74 is configured to modify the drive signal based on at least one setting for at least one load device 75. The output filter 74 may include: one or more active components including an SCR, a Field Effect Transistor (FET), and an insulated gate bipolar transistor (IGPT); and one or more passive components such as capacitors, inductors, and resistors. The at least one setting may include a physical parameter of the load device 75, a tilt setting for driving on a slope, a decline, or a incline, a turn setting for a low radius turn, a load setting for a motor, a fuel efficiency setting, or a configuration setting. Each of these examples is described in more detail in the following sections. As shown in fig. 32B, the at least one load device 75 may be a motor, such as a Direct Current (DC) motor, an AC induction motor, a synchronous AC motor, a brushless DC motor, a brushed DC motor, or a combination of multiple of the foregoing designs.

The controller 71 is configured to generate control signals for setting a plurality of switch states to generate drive signals for the at least one motor. The control signal may be based on sensor data. Examples of sensor data include stem steering sensor data, load sensor data, or orientation sensor data.

Power system device examples

The power system apparatus includes a synchronous inverter and at least one motor driven by the synchronous inverter. In one example, a synchronous inverter drives one or more wheels of a vehicle. The power system may include a plurality of synchronous inverters, each of which is electrically coupled to a different motor. Further, the power system may include a plurality of motors driven by a single inverter.

The power system equipment may include an electronic hybrid power system for a lawn mower or other vehicle. An electric hybrid power system may include a synchronous inverter and a motor for each of a plurality of drive wheels. The electric motor and the drive wheel may be independently driven according to the techniques described herein. The hybrid power system may include at least one battery that is charged by the alternator at a first time or during a portion of a power cycle and subsequently powers the at least one motor at a second time or during a portion of the power cycle.

Fig. 33 illustrates an exemplary vehicle 80 including a synchronous inverter and at least one motor. The vehicle 80 includes an engine 12, a generator 13, and a synchronous inverter 11. The vehicle 80 may also include an output filter 74. The vehicle 80 includes a motor 81, a gear assembly 82, wheel links 83, one or more idler gears 84, one or more driven wheels 85, a flywheel 88 on a drive shaft 89 (fig. 35), and a sub-frame including a support frame 86 and a gear frame 87. The motor 81 may be a Direct Current (DC) motor controlled by voltage or an Alternating Current (AC) motor controlled by frequency. In addition, different or fewer components may be included.

Synchronizing the inverter and at least one motor is an exemplary alternative to replacing a hydraulic propulsion system used on, for example, a Zero Turn Radius (ZTR) lawn mower. The hydraulic propulsion system operates the two drive machines and the drive wheels independently. Conventional ZTR lawn mowers may include a hydraulic valve to control a belt driven hydrostatic transmission from an internal combustion engine, which may fuel gasoline, diesel fuel, liquefied petroleum gas (LP), Compressed Natural Gas (CNG), or another type of combustible fuel. Hydrostatic transmissions require periodic maintenance to maintain performance and durability. In addition, hydraulic fluid may leak, causing environmental damage (e.g., grass damage or garage floor contamination).

On the other hand, similar lawn mowers using electric propulsion eliminate these challenges and achieve new advantages and features. A lawn mower using an electric propulsion and synchronous inverter may include: traction control to prevent damage to the turf by one or both wheels; zero radius turning technology to prevent one wheel from damaging the turf; optimization of engine speed for a given ground speed when load changes (e.g. uphill, downhill, or on sand); and/or optimization of engine speed (and fuel consumption) for power consumed by load changes when used with electric motor drives.

FIG. 34 illustrates exemplary sub-assemblies of the vehicle of FIG. 33. FIG. 35 shows a reverse diagram of the exemplary sub-components of FIG. 34. Fig. 36 shows a top view of the exemplary subassembly of fig. 34.

The subassembly may include a sub-frame including a support frame 86 and a gear frame 87. The support frame 86 is secured to the gear frame 87 using one or more connectors. The term connector as used throughout may include any combination of bolts, screws, rivets or weld joints. Alternatively, the support frame 86 and the gear frame 87 may be integrally formed. The gear frame 87 is mechanically coupled to the gear assembly using one or more connectors. The support frame 86 is mechanically coupled to the engine 12, the alternator 13, and the one or more motors 81 using one or more connectors, wherein the alternator 13 may include the synchronous inverter 11.

The subassemblies may be pre-assembled into a hybrid power system module. The support frame 86 may be coupled to the chassis of the vehicle using support bars 91. The support frame 86 may include brackets that are slidable onto the support bars 91, and the assembly may be secured to the chassis of the vehicle using one or more connectors. Accordingly, any combination of the engine 12, the alternator 13, the synchronous inverter 11, the one or more motors 81, the one or more gear transmissions 82, the one or more wheel links 83, the support frame 86, and the gear frame 87 may be simultaneously coupled to the vehicle 80 using subassemblies. In one example, the only mechanical connector between the subassembly and the vehicle 80 is made by the support bar 91.

The subassembly may also be connected to the vehicle by an electrical connector. The electrical connections include accessories for the vehicle 80. That is, the subassembly including the alternator 12 or the synchronous inverter 11 may provide a DC output to operate accessories of the vehicle 80, such as lights, a radio, a mower deck ladder, gauges, a control panel, or other features. In one example, the high voltage circuit associated with the alternator 12 or the synchronous inverter 11 is isolated from the electrical connection between the subassembly and the vehicle 80. The subassembly can be installed without exposure to any high voltage parts. The subassembly may be installed by a user or technician that is not trained in the high voltage equipment.

The controller 71 determines a drive signal for the load device 75 and generates a control signal for synchronizing the switching of the inverter 11. The synchronous inverter 11 outputs the drive signal, which may be modified by an output filter 74. The drive signal may include a frequency for specifying the speed of the motor 81. The motor 81 rotates a shaft in the gear transmission 82 at an input speed, and the gear transmission 82 changes the input speed to an output speed. The gear assembly 82 may include a series of gears having different gear ratios to convert an input speed to an output speed. Alternatively, the motor may be directly coupled to the wheels without a transmission.

The gear transmission 82 may be a right angle gearbox that transmits the mechanical output of the electric motor 81 to the drive wheels 85 of the vehicle 80. The gear transmission 82 may include a worm gear for transmitting a rotation direction of a driving shaft of the motor 81 to a rotation direction of the wheel link 83. The wheel link 83 is coupled to the driving wheel 85 and applies a rotational force to the driving wheel 85.

Alternatively, when the gear assembly 82 includes a worm drive gear reduction system, no braking system is required because the output shaft is naturally locked unless the input shaft is rotating. Additionally, an override clutch may be included in the gear assembly 82 for disengaging one or more gears. When the override clutch is engaged, the drive wheels 85 are free to independently operate the gear assembly 82. Thus, when the override clutch is engaged, the vehicle 80 may be moved or propelled manually or in a motoring manner without the need for the motor 81 to rotate the gear assembly 82. In another example, the gear assembly 82 may include one or more limits to set the maximum speed of the drive wheels. Alternatively, the motor may incorporate spring action and electrically released braking to prevent accidental movement of the vehicle 80.

Fig. 37 shows a perspective view of a vehicle 80 as a Zero Turn Radius (ZTR) lawn mower. The mower includes drive wheels 85, idler wheels 84, a mower deck 95, and one or more control levers 93. The subassemblies of fig. 34-36 may include a mechanical connection to one or more levers 93 to transmit user input levels as at least one setting for the motor 91. One or both of the control levers may be interchangeable with a joystick or another steering mechanism.

One or both of the control levers 93 may be matched with a position sensor. The position sensor may comprise an optical sensor, a potentiometer or resistance sensor, a displacement sensor or a rotation sensor. When the control lever 93 is rotated forward or backward, the position sensor determines the direction and amount of rotation. The position sensor may generate an output proportional to the rotation of the control lever 93. The output of the position sensor for each control lever 93 is analyzed by the controller 71 to generate a control signal for the synchronous inverter 11, the synchronous inverter 11 outputting drive signals for the engine 81 and the corresponding drive wheels 85. The controller 71 may determine the position of the control lever 93 based on the sensor data.

The controller 71 may include: a lookup table correlating the position of the position sensor with each gear shift stage of the motor 81, a drive signal level corresponding to each gear shift stage of the motor 81, or a setting of the synchronous inverter 11 corresponding to each gear shift stage of the motor 81. The look-up table may be based on the responsiveness of the hydraulic system. That is, the look-up table may be selected to cause the controller 71 to simulate a hydraulic system. That is, if a 10 degree rotation in the control lever 93 before a target rotation of 20 revolutions per minute is applied in the hydraulic system would result in a 0.5 second delay, the look-up table may instruct the synchronous inverter 11 to delay for 0.5 seconds and then generate a drive signal that causes the motor 81 to rotate at 20 revolutions per minute. Alternatively, the look-up table may be selected to specify the torque applied to the drive wheels 85, and the drive wheels 85 may simulate a hydraulic system.

Electronic control of mower

The controller 71 may provide various additional controls for transmitting position sensor data of the control lever 93 to the driving signal from the synchronous inverter 11 for driving the motor 81. The additional control may include: a turn setting for turf protection, a tilt setting for safety, a turn setting for a tilt plane, an optimized mowing setting, and a traction control setting.

The cornering arrangement for turf protection can avoid the drive wheel 85 damaging the turf when one wheel is driving while the other remains stationary. When one wheel remains stationary, it can spin in place as the other moves forward. The wheels slip in place and may damage the turf, pulling the grass off the ground.

The controller 71 can recognize this situation and reduce the risk of damage. The controller 71 may identify this type of turn (e.g., a potentially sod destructive turn) when one lever 93 is pushed forward or backward beyond a threshold position and the other lever 93 is held in a substantially fixed position. The outboard wheels of the vehicle 80 correspond to the control lever 93 being pushed forward or rearward beyond a threshold position, and the inboard wheels of the vehicle 80 correspond to the control lever 93 being held in a substantially fixed position. The substantially fixed position may be a position deflection of 0 degrees or within a predetermined range of 0 degrees. Examples of the predetermined range may include a range of 5 degrees, a range of 10 degrees, or a range of 15 degrees. Examples of threshold positions indicating forward or backward may be 30 degrees, 40 degrees or 50 degrees.

When a potentially turf destructive turn is identified, the controller 71 adjusts the control signal for the synchronous inverter 11 and the corresponding drive signal for the drive wheels 85. The controller 71 may deliver a control signal in normal conditions as to one of the levers 93 pushing forward or backward beyond a threshold position. The controller 71 may modify the control signals for the wheels in the substantially fixed position. The controller 71 may generate control signals for synchronizing the inverter 11 and corresponding drive signals for the drive wheels 85 to introduce nominal regulation, feathering, or multiple directional control. Nominal adjustments may include incremental increases or decreases in speed added to the inboard wheel associated with a substantially fixed position. The speed increment or decrement may be a nominal (e.g., 1 revolution per minute or 1 inch per second) adjustment made by the inboard wheel speed. Feathering or multiple directional control may include a series of adjustments to the inboard wheel associated with the substantially stationary position. The controller 71 may cause the inner wheel to be pushed forward for a first time, rotated backward for a second time, and repeated between the forward and backward movements. Further, the controller 71 may include hysteresis control such that if the user adjusts the control of the inner wheel, which typically provides nominal speed or feathering control of the inner wheel, the controller 71 keeps the automated speed of the inner wheel incremented or decremented instead of being provided by the user until the user input exceeds a threshold set by the hysteresis control.

The controller 71 may provide a tilt setting for safety. The controller 71 may receive data from inertial sensors coupled to the vehicle 80. The inertial sensors may include any combination of accelerometers, magnetic sensors, or gyroscopes. The orientation data may describe a maximum of three angles, such as roll, pitch, and yaw of the vehicle. The orientation data may include a total angle value (e.g., a sum of roll and pitch angles) describing a sum of the angular differences relative to the horizontal plane.

The controller 71 may determine whether the vehicle 80 is traveling uphill or downhill based on at least one of the angles (e.g., pitch angle). The controller 71 may adjust the speed or braking mechanism of the vehicle 80 to reduce the risk of the vehicle 80 tipping over or the risk of one or more of the wheels moving off the driving surface. When the orientation data indicates that the pitch angle of the vehicle 80 exceeds a threshold (e.g., the pitch angle of the vehicle 80 is greater than a positive angle threshold or less than a negative angle threshold), it may be determined whether the vehicle 80 is to travel uphill or downhill.

When the vehicle is traveling uphill, the controller 71 may adjust the speed of the motor 81 by increasing the speed of the motor 81 or the speed of the engine 12 by adjusting the control signal for the synchronous inverter 11 and the corresponding drive signal for the drive wheels 85 when the pitch angle exceeds an uphill threshold. When the vehicle is traveling downhill, the controller 71 may adjust the speed of the motor 81 by reducing the speed of the motor 81 or the speed of the engine 12 by adjusting the control signal for the synchronous inverter 11 and the corresponding drive signal for the drive wheels 85 when the pitch angle exceeds a downhill threshold.

In addition, the controller 71 may selectively remove current from the electrical release mechanism (if equipped) of the brakes on the wheels. The controller 71 may also apply a reverse rotating field to the motor to provide a reversing torque. This may be used to load the engine 12 to prevent an engine overspeed condition.

The controller 71 may provide a steering arrangement for the inclined surface. The controller 71 may receive data from inertial sensors coupled to the vehicle 80. The azimuth data may describe the roll angle for turning of the inclined plane. The roll angle is substantially non-zero and substantially constant when the vehicle is traveling along a slope. One set of wheels (e.g., the right side) of a vehicle traveling along a slope is higher in elevation than the other set of wheels (e.g., the left side). The controller 71 may determine that the roll angle is greater than a minimum tilt value (e.g., 10 degrees or 5 degrees) and is consistent with a predetermined variance (e.g., 10% or other percentage) over a period of time. The vehicle traveling along the slope may be a lawn mower traveling perpendicular to the hill.

ZTR mowers that travel along a slope may remain particularly difficult in the forward direction. Due to gravity, the vehicle 80 may tend to steer in a downhill direction. The operator of the ZTR lawnmower may develop a lever that holds the downhill wheels slightly more skillfully in the forward direction (as compared to the uphill wheels). The controller 71 may supplement such control. The controller 71 may identify when a user input regarding forward driving occurs when the roll angle is greater than the minimum inclination value and coincides with a predetermined variance for a certain period of time. In response, the controller 71 may adjust the speed of the downhill motor to be greater than the speed of the uphill motor. For example, the controller 71 may regulate the control signal for the synchronous inverter 11 and the corresponding drive signal for the drive wheels 85 of the downhill motor.

When the vehicle 80 is traveling on a slope, the controller 71 may adjust the control signal for the synchronous inverter 11 in response to the slope, and effectively adjust the drive signal for the drive wheels 85.

The controller 71 may provide an optimized mowing setting based on sensor data regarding turf. The sensor data may comprise a moisture sensor which detects when present on moist grass. The controller 71 may increase the speed of the engine 12 in response to a demand for increased power requirements such as a heavier load when cutting tall and rough grass or wet grass. Thus, the alternator 13 provides a higher output voltage (e.g., a DC motor), or frequency and/or voltage (if an AC motor), to maintain mower blade speed. Conversely, at light loads, the controller 71 will reduce the engine speed. The controller 71 causes the synchronous inverter 11 to maintain an electrical output to maintain the selected motor speed.

The controller 71 may provide traction control settings based on slip sensor data from the drive wheels 85. For example, each drive wheel 85 may be associated with a speed sensor or position sensor for tracking the movement of the drive wheel 85 and generating data indicative of the speed or position of the drive wheel 85. The controller 71 compares the speed and/or position of the drive wheels 85 to determine if one drive wheel 85 is traveling significantly faster or slower than the other drive wheel 85. The controller 71 may compare the speed difference of the wheels to a traction threshold to determine whether slip has occurred. Slippage may occur due to wet surfaces (e.g., wet trailer ramps, wet slippery road surfaces, wet grass), mud, or unstable surfaces (e.g., loose stones). In response to determining slip, the controller 71 may apply traction control by generating a command regarding the brakes applying a braking force to the one or more drive wheels 85. In one example, a braking force may be applied to a faster (e.g., slipping) wheel.

Monitor characteristics

The controller 71 may adjust the control signal for synchronizing the inverter 11 based on the characteristics of the motor 81. In one example, the physical characteristics may include a structural size of the motor 81 or an amount of metal constituting the motor 81. The electrical characteristics may include pitch, number of poles or number of coils of the motor 81. The characteristics of the motor 81 may define a resonance frequency of harmonics generated by the motor 81 or noise or vibration generated by the motor 81, and the adjusting the control signal for synchronizing the inverter 11 may include adjusting the target waveform to minimize the generated harmonics in the motor.

The controller 71 may receive data indicative of characteristics from a sensor, such as a vibration sensor. The controller 81 may receive data indicative of characteristics from user input, such as settings for the model or manufacturer of the installed motor 81. The controller 81 may access data indicative of characteristics from a memory that includes a table of motor models and characteristics.

The characteristics of the motor 81 may be associated with an ideal waveform. The ideal waveform may include a frequency tuned to a particular motor 81. The frequency may be spaced from the resonant frequency by a set amount to reduce vibration. The frequencies may be selected to reduce harmonics. Using an ideal waveform will result in less internal heat being generated by the motor 81, which will improve system efficiency.

The controller 71 may adjust the control signal for synchronizing the inverter 11 so that a desired waveform is applied to the motor 81. The subassembly may be assembled prior to calibrating the controller 71 and the synchronous inverter 11 according to the characteristics of the motor 81. In this way, harmonics and resonant frequencies of the sub-assemblies are measured prior to installation in the vehicle 80, further reducing the manufacturing burden when assembling the vehicle 80. The calibration eliminates or attenuates vibrations or harmonics generated internally by the subassembly.

Closed-loop sub-cycle target control (voltage, current)

Typical inverters (DC-AC or AC-AC) are regulated to a Root Mean Square (RMS) voltage rather than a sinusoidal target. Tuning to a sinusoidal target allows the sub-period to respond (faster) to changes in the load on the generator or vehicle. The synchronous inverter 11 can respond more quickly to changes. The term sub-period refers to a change that occurs at a period less than the period of the drive signal output from the synchronous inverter 11.

Maintaining more efficient use of fuel

The controller 71 may implement an optimal operational sequence for the engine 12, the generator 13, and the synchronous inverter 11 based on the requirements of the vehicle 80. For example, controller 71 may execute a hybrid algorithm: switching between the power generated in the alternator 13 and the energy stored in the one or more batteries.

In one example, the controller 71 implements optimal operating characteristics with respect to the charging cycle of the battery and the at least one motor 81. The optimal operating characteristic of the engine 12 may be a predetermined percentage (e.g., 80%) of the output of the engine 12 or the speed of the engine 12. Even when the load demand is low, the engine 12 is operating at an optimum capacity and any excess is stored in the battery. The controller 71 may determine when one or more batteries read sufficient charge or a particular charge level and shut down the engine 12 and alternator 13 at that time. The synchronous inverter 11 then operates with the energy stored in the battery until the battery reaches a minimum level. At this point, the engine 12 is again started and operated at the optimum level. The sequence is repeated.

Configuration detection

The controller 71 may determine the electrical configuration of the synchronous inverter 11 based on the load connected with the synchronous inverter 11. The electrical configuration may indicate a single phase load or a three phase load. The electrical configuration may be a load characterization, which may indicate the type of load connected to the synchronous inverter 11.

The controller 71 may determine whether the load is single-phase or three-phase based on the test signal. For example, consider the three outputs of the synchronous inverters (a, B, C). The controller 71 may send a test voltage to one of the outputs (a) and measure the resulting voltage on one or more of the other outputs (B, C). When the other outputs (B, C) are measured to be at substantially similar levels as the test voltage, the controller 71 determines that the load is single-phase. Otherwise, the controller 71 determines that the load is three-phase.

The controller 71 may also determine the type of load based on the test signal. Exemplary types of loads include resistive, nonlinear, capacitive, inductive, and reactive. For example, the non-linear load includes a battery charger, an Uninterruptible Power System (UPS), or a Variable Frequency Drive (VFD). The controller 71 is configured to: the gain of the synchronous inverter 11 is adjusted by controlling the state of the switches in the signal in response to the load characteristics of the load of the segmented waveform converter.

Controller 71 may identify the sub-cycle load change based on the type of load. For example, the non-linear load may include a load peak occurring at a particular time of the cycle. Load spikes may occur when the SCR triggers at a particular sub-cycle position (e.g., 60 degrees). The controller 71 may modify the control signals for the synchronous inverter 11 so that the output of the synchronous inverter is increased at a predetermined time (e.g., a set number of milliseconds) or at a set position of the cycle prior to the predicted load peak. The pre-change in output may reduce power droop that may occur after load peaks. Similar control can be applied to the reduction of the load to avoid power overshoot.

Power signal transfer between synchronous inverters

As described above in connection with fig. 19-28, multiple synchronous inverters may be connected together to provide power to loads in parallel (to provide an increased current output) or to loads in series (to provide an increased voltage output). Synchronous inverters may also communicate with each other using synchronization signals to match the phase angle between different inverters to regulate their supply voltages using a communication network. In addition or in the alternative, the controller 71 may generate a communication signal that is modulated on the output drive signal of the synchronous inverter 11 through a communication interface. The communication signal may be a high frequency signal encoded with data using frequency modulation or pulse width modulation. The modulated communication signal may be high enough in frequency so as not to interrupt operation of the motor or other load, but still be detectable by the controller for use in other synchronous inverters in the system.

The synchronous inverters may communicate to balance the load and ensure equal wear among a group of connected synchronous inverters 11. For example, for a 25kW load and four synchronous inverters, the inverters may communicate with their loads such that each synchronous inverter tends to supply 6.26kW to the load.

Fig. 38 shows a flowchart regarding the operation of the controller 71, wherein the operation of the controller 71 can be realized by the generator controller of fig. 16. In addition, different or fewer acts may be included.

At act S301, the processor 300 is configured to receive a feedback signal at an input coupled to the controlled field alternator. The feedback signal may be indicative of the current output of the controlled field alternator. Processor 300 may access the targets output from memory 352 or receive the targets output from communication interface 353 from workstation 359 or another synchronous inverter.

At action S303, the processor 300 generates a drive signal for the at least one motor at a segmented waveform converter or synchronous inverter comprising a switch connected to a feedback signal of the controlled field alternator. At action S305, the processor 300 modifies the drive signal based on at least one setting for the motor. The at least one setting may include a physical parameter of the load motor, a tilt setting for driving on a slope, a decline, or a incline, a turn setting for a low radius turn, a load setting for the motor, a fuel efficiency setting, or a configuration setting.

The processor 300 may include a general purpose processor, a digital signal processor, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), an analog circuit, a digital circuit, a combination thereof, or other now known or later developed processor. The processor 300 may be a single device or a combination of devices, for example, associated with a network, distributed processing, or cloud computing.

The memory 352 may be volatile memory or non-volatile memory. The memory 352 may include one or more of Read Only Memory (ROM), Random Access Memory (RAM), flash memory, Electrically Erasable Programmable Read Only Memory (EEPROM), or other types of memory. The memory 352 may be removable from the network device, such as a Secure Digital (SD) memory card.

Communication interface 303 may include any operable connections in addition to ingress and egress ports. An operable connection may be one in which signals may be sent and/or received, physical communication, and/or logical communication. An operable connection may include a physical interface, an electrical interface, and/or a data interface.

Communication interface 353 may connect to a network. The network may include a wired network (e.g., ethernet), a wireless network, or a combination thereof. The wireless network may be a cellular telephone network, an 802.11, 802.16, 802.20, or WiMax network. Additionally, the network may be a public network such as the Internet, a private network such as an intranet, or a combination thereof, and may utilize various networking protocols now available or later developed, including but not limited to TCP/IP based networking protocols.

While the computer-readable medium (e.g., memory 352 or database 357) is shown as a single medium, the term "computer-readable medium" includes a single medium or multiple media, such as a centralized or distributed database, and/or associated caches and servers that may store one or more sets of instructions. The term "computer-readable medium" shall also be taken to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by a processor or that cause a computer system to perform any one or more of the methodologies or operations disclosed herein.

In certain non-limiting example embodiments, the computer-readable medium may include solid-state memory, such as a memory card, or other package that houses one or more non-volatile read-only memories. Further, the computer readable medium may be a random access memory or other volatile rewritable memory. Further, the computer readable medium may include a magneto-optical or optical medium such as a disk or tape, or other storage device for capturing a carrier wave signal such as a signal transmitted over a transmission medium. A digital file attachment to an email or other self-contained information archive or set of archives may be considered a distribution medium, i.e., a tangible storage medium. Accordingly, the present disclosure is considered to include any one or more of a computer-readable medium or a distribution medium and other equivalent and successor media, in which data or instructions may be stored. The computer readable medium may be non-transitory, i.e., include all tangible computer readable media.

In alternative embodiments, dedicated hardware implementations, such as application specific integrated circuits, programmable logic arrays and other hardware devices, can be configured to implement one or more of the methodologies described herein. Applications that may include the apparatus and systems of various embodiments may broadly include a variety of electronic and computer systems. One or more embodiments described herein may implement functions using two or more specific interconnected hardware modules or devices with related control and data signals that may be communicated between and through the modules, or as part of an application-specific integrated circuit. Accordingly, the present system includes software implementations, firmware implementations, and hardware implementations.