阅读说明：本技术 飞行器启动和发电系统 (Aircraft starting and generating system ) 是由 黄豪 贾小川 马尼什·阿什文库马尔·达拉尔 于 2021-06-04 设计创作，主要内容包括：一种飞行器启动和发电系统,包括：启动器/发电机；以及逆变器/转换器/控制器,其连接到启动器/发电机,并且在启动模式下生成AC电力以驱动启动器/发电机,从而启动飞行器的原动机,并且在启动器/发电机的发电模式下,将在原动机已经启动之后从启动器/发电机获得的AC电力转换为DC电力。四臂逆变器与DC电力输出联接,并具有带有基于MOSFET的四臂桥构造的逆变器/转换器/控制器(ICC),其在启动模式下驱动启动器/发电机,从而启动飞行器的原动机,并在启动器/发电机的发电模式下将DC电力转换为AC电力。四臂桥栅极驱动器被构造为在启动和发电模式期间使用脉冲宽度调制(PWM)驱动基于MOSFET的四臂桥。(An aircraft starting and generating system comprising: a starter/generator; and an inverter/converter/controller connected to the starter/generator and generating AC power to drive the starter/generator in a start mode to start the prime mover of the aircraft and converting AC power obtained from the starter/generator after the prime mover has been started to DC power in a generate mode of the starter/generator. A four-arm inverter is coupled to the DC power output and has an inverter/converter/controller (ICC) with a MOSFET-based four-arm bridge configuration that drives the starter/generator in a start mode to start a prime mover of the aircraft and converts the DC power to AC power in a generate mode of the starter/generator. The four-arm bridge gate driver is configured to drive the MOSFET-based four-arm bridge using Pulse Width Modulation (PWM) during start-up and power generation modes.)

1. An aircraft starting and generating system, comprising:

a starter/generator comprising a main machine and a permanent magnet generator;

a Direct Current (DC) power output from the starter/generator;

a four-arm inverter coupled with the DC power output and having an inverter/converter/controller (ICC) with a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) based four-arm bridge configuration, and that generates DC power to drive the starter/generator in a start mode to start a prime mover of the aircraft, and that converts DC power obtained from the starter/generator after the prime mover has been started to Alternating Current (AC) power in a generate mode of the starter/generator; and

a quad bridge gate driver configured to drive the MOSFET-based quad bridge;

wherein the four-arm bridge gate driver operates using Pulse Width Modulation (PWM) to drive the MOSFET-based four-arm bridge during a start-up mode and a generate mode.

2. The aircraft starting and generating system of claim 1 wherein the MOSFET-based four-armed bridge configuration further comprises three arms each having a single phase output of a three phase AC output, and a fourth arm having a neutral output.

3. The aircraft starting and generating system of claim 2 wherein the three-phase AC output is 400 Hz.

4. The aircraft starting and generating system of claim 1 wherein the MOSFET-based four-armed bridge further comprises at least one of a silicon carbide-based bridge or a gallium nitride-based bridge.

5. The aircraft starting and generating system of any one of claims 1-4 wherein the starter/generator is an induction generator.

6. The aircraft starting and generating system of claim 5 wherein the permanent magnet generator establishes an induced voltage for the induction generator.

7. The aircraft starting and generating system of any one of claims 1-4 further comprising: a MOSFET-based main machine bridge connected to a stator of a main machine; and a host bridge gate driver configured to drive the MOSFET-based host bridge.

8. The aircraft starting and generating system of claim 7 wherein the configuration of the MOSFET-based main machine bridge is operable in a regeneration mode to absorb excess power of the system by storing the excess power in kinetic energy of the prime mover of the aircraft, and wherein the main machine bridge gate driver is operative to drive the MOSFET-based main machine bridge using space vector pulse width modulation during a regeneration mode.

9. A method of controlling an aircraft starting and generating system, the aircraft starting and generating system having: an inductive starter/generator comprising a main machine having a DC power output and a permanent magnet generator; a four-arm converter coupled with the DC power output and having an inverter/converter/controller (ICC) with a MOSFET-based bridge configuration; and a four-arm bridge gate driver configured to drive a MOSFET-based bridge, the method comprising:

supplying power to the MOSFET-based quadrifilar bridge if in a start mode and driving the MOSFET-based quadrifilar bridge using Pulse Width Modulation (PWM) during the start mode, and wherein driving the MOSFET-based main bridge during the start mode starts a prime mover of the aircraft; and

driving the MOSFET-based quadrifilar bridge using PWM to convert DC power derived from the DC power output of the starter/generator to quadrifilar AC power if in generate mode.

10. An aircraft, characterized in that it comprises:

an engine;

an induction starter/generator connected to the engine and having a main machine and a permanent magnet generator;

a Direct Current (DC) power output from the inductive starter/generator;

a four-arm inverter coupled with the DC power output and having an inverter/converter/controller (ICC) with a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) based four-arm bridge configuration and generating DC power to drive the starter/generator in a start mode to start the engine and converting DC power obtained from the starter/generator after the engine has been started to Alternating Current (AC) power in a generate mode of the induction starter/generator; and

a quad bridge gate driver configured to drive the MOSFET-based quad bridge;

wherein the four-arm bridge gate driver is operative to drive the MOSFET-based four-arm bridge using Pulse Width Modulation (PWM) during a start-up mode and a generate mode.

Technical Field

The present disclosure relates to methods and apparatus for operating a starting and generating system by operating a bridge gate (gate) driver system of a set of switchable modules.

Background

The subject matter disclosed herein relates generally to a combination of a bidirectional energy converting brushless electric rotating device that converts electrical energy to mechanical energy in a start mode and mechanical energy to electrical energy in a generate mode. In particular, the subject matter relates to aircraft starting and generating systems that include a three-machine consist, a starter/generator (S/G) and an IGBT-based digital control device, referred to herein as an inverter/converter/controller (ICC) or an induction generator (e.g., a dual-machine consist).

There currently exist starter generator systems for aircraft that are used to start aircraft engines and utilize the aircraft engines after they are started in a generating mode to provide electrical power to the power systems on the aircraft. Direct Current (DC) or high voltage direct current (HVDC, e.g., a voltage equal to or greater than 270VDC) power may be obtained from an aircraft turbine engine driven generator and converter (EGC). Alternating Current (AC) power may be obtained from an AC generator driven by the aircraft turbine engine, or from conversion of DC power to AC power. It is known to use wide bandgap devices to achieve efficiency in the high voltage DC system of an aircraft turbine EGC or in the DC link voltage generated from an AC generator driven by the aircraft turbine engine. Also, it is known to use wide bandgap devices to achieve efficiency in the AC system of an aircraft turbine EGC or in the AC link voltage from an aircraft turbine engine driven DC generator. Low switching losses, low conduction losses and high temperature capability are three advantages of wide bandgap devices.

It is desirable to control wide bandgap devices in the power generation system of an aircraft to consistently achieve desired efficiencies.

Disclosure of Invention

In one aspect, the present disclosure is directed to an aircraft starting and generating system comprising: a starter/generator comprising a main machine and a permanent magnet generator; a Direct Current (DC) power output from the starter/generator; a four-arm (leg) inverter coupled to the DC power output and having an inverter/converter/controller (ICC) having a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) based four-arm bridge configuration and that, in a start mode, generates DC power to drive the starter/generator to start a prime mover of the aircraft and that, in a generate mode of the starter/generator, converts the DC power obtained from the starter/generator after the prime mover has been started to Alternating Current (AC) power; and a four-arm bridge gate driver configured to drive the MOSFET-based four-arm bridge, wherein the four-arm bridge gate driver operates using Pulse Width Modulation (PWM) to drive the MOSFET-based four-arm bridge during start and generate modes.

In another aspect, the invention relates to a method of controlling an aircraft starting and generating system having: an induction starter/generator comprising a main machine having a DC power output and a permanent magnet generator; a four-arm converter coupled with the DC power output and having an inverter/converter/controller (ICC) having a MOSFET-based bridge configuration; and a four-arm bridge gate driver configured to drive the MOSFET-based bridge, the method comprising: supplying power to the MOSFET-based four-arm bridge if in a start mode, and driving the MOSFET-based four-arm bridge using Pulse Width Modulation (PWM) during the start mode, and wherein driving the MOSFET-based main bridge during the start mode starts a prime mover of the aircraft; and if in generate mode, driving the MOSFET-based four-arm bridge using PWM to convert DC power obtained from the DC power output of the starter/generator to four-arm AC power.

In another aspect, the present disclosure is directed to an aircraft comprising: an engine; an induction starter/generator connected to the engine and having a main machine and a permanent magnet generator; a Direct Current (DC) power output from the inductive starter/generator; a four-arm inverter coupled with the DC power output and having an inverter/converter/controller (ICC) having a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) based four-arm bridge configuration and generating DC power to drive the starter/generator in a start mode to start the engine and converting the DC power obtained from the starter/generator after the engine has been started to Alternating Current (AC) power in a generation mode of the induction starter/generator; and a four-arm bridge gate driver configured to drive the MOSFET-based four-arm bridge, wherein the four-arm bridge gate driver operates to drive the MOSFET-based four-arm bridge using Pulse Width Modulation (PWM) during start-up and generate modes.

These and other features, aspects, and advantages of the present disclosure will become better understood with reference to the following description and appended claims. The accompanying drawings incorporated in and forming a part of the specification illustrate aspects of the present disclosure and, together with the description, serve to explain the principles of the disclosure.

Drawings

A full and enabling disclosure of the present description, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:

FIG. 1 illustrates an example environment for the entire S/G and ICC engine cranking and power generation system of the present subject matter.

FIG. 2 is a block diagram of the entire S/G and ICC engine cranking and power generation system of FIG. 1.

FIG. 3 is a block diagram of the S/G and ICC engine cranking and power generation system of FIGS. 1 and 2 in a start mode.

FIG. 4 is a block diagram of the S/G and ICC engine cranking and power generation system of FIGS. 1 and 2 in a power generation mode.

FIG. 5 is a cross-sectional view of the S/G of FIG. 1.

FIG. 6 is a block diagram of an S/G and ICC engine starting and generating system with a MOSFET-based host bridge.

Fig. 7 is an exemplary circuit diagram of a reverse conduction based passive (inactive) rectifier MOSFET switching method.

FIG. 8 is a block diagram of an S/G and ICC engine starting and generating system with a load balancing unit having a MOSFET-based bridge.

FIG. 9 is a block diagram of an S/G and ICC engine starting and generating system with a MOSFET-based four-arm bridge.

FIG. 10 is a cross-sectional view of another starting and generating system in the form of an induction generator.

Fig. 11 is a block diagram of a starting and generating system including the induction generator of fig. 10 and having a MOSFET-based four-armed bridge.

Fig. 12 is a block diagram of a starting and generating system including the induction generator of fig. 10 and having a MOSFET-based main machine bridge, and configured to supply HVDC power output.

Detailed Description

In one aspect of the present disclosure, the subject matter disclosed herein may be used in systems such as those shown in FIGS. 1-12, and the S/G and ICC engine cranking and power generation system 50 includes S/G100 and ICC 200. As shown in fig. 1, 2 and 5, the S/G100 is a combination of three motors including a main body 110, an exciter 120 and a PMG 130. This arrangement is called a triad. The host 110 may be a salient pole synchronous machine. The stator 112 of the main machine 110 is connected to the main IGBT/diode bridge 210 of the ICC 200. The rotor 114 of the main machine 110 is connected to the output of a full-wave or half-wave rotating rectifier 116 located inside the shaft 118 of the main rotor 114. Exciter rotor 122 has three phase windings connected to the input of rotary rectifier 116 and exciter stator 124 includes DC windings and three phase AC windings connected to exciter IGBT/diode bridge 212 of ICC 200 through contactor 220 shown in fig. 2. Fig. 2 provides a block diagram of the S/G and ICC system 50, focusing on the components that make up the main IGBT/diode bridge 210 and the exciter IGBT/diode bridge 212.

The ICC 200 shown in fig. 2 includes two IGBT/diode bridges: a host bridge 210 and an exciter bridge 212. The main bridge 210 and exciter bridge 212 are also referred to as a main inverter/converter and an exciter inverter/converter, respectively. Both the main bridge 210 and the exciter bridge 212 are controlled by a digital control assembly. The components that control the main IGBT/diode bridge 210 are referred to as main digital control components 230. Alternatively, the components controlling the main IGBT/diode bridge 210 may also be referred to as starter inverter digital control components in the start mode and as generator converter control components in the generate mode. The assembly that controls the exciter IGBT/diode bridge 212 is referred to as an exciter digital control assembly 240. Alternatively, the assembly controlling the exciter IGBT/diode bridge 212 may also be referred to as an exciter inverter digital control assembly in the start mode and as an exciter inverter digital control assembly in the generate mode. The main digital control assembly 230, along with its embedded software, controls the main bridge 210, which main bridge 210 generates AC power to drive the S/G in a start-up mode and converts the AC power to DC power required on-board the aircraft in a generate mode.

The S/G and ICC engine start and power generation system 50 has two modes of operation: a start-up mode and a power generation mode. In the start-up mode, the S/G and ICC system 50 is powered by the individual power supply VDC 60, whereby the connection to the individual power supply VDC 60 is shown in fig. 1 and 2. The main machine 110 functions as a three-phase wound field (field) salient pole synchronous motor in a start mode. Two situations may occur where torque is generated at the shaft of a synchronous motor. The first is to input three-phase alternating current to the three-phase windings of the main stator 112, and the second is to supply excitation current to the main rotor 114. The frequency of the current supplied to the main stator 112 is proportional to the speed of the main machine. Three-phase ac power is provided by the main IGBT/diode bridge 210. The rotating field generated by the three-phase current interacts with the magnetic field generated by the main rotor 114, thereby generating a mechanical torque at the shaft of the main rotor 114.

In conventional power generation systems, providing excitation current to main rotor 114 is a challenge. At the start of the start-up, no power is generated by any synchronous machine based exciter. At low speeds, synchronous machine-based exciters cannot generate enough power to power the main rotor. This is because for any synchronous based exciter, its DC excitation winding does not transfer power to the rotor windings. In fact, with conventional power generation systems, power can only be transferred from the mechanical energy on the shaft. Therefore, to start the engine, the power to generate the main rotor excitation current must come from the exciter stator 124. In other words, the energy used for excitation passes through the air gap of the exciter 120 during the start-up mode. A rotary transformer is required. In contrast, in the generating mode, the main machine 110 functions as a three-phase wound field salient pole synchronous generator. To generate electricity, an excitation current is provided to the main rotor 114. Conventional synchronous exciters may be used for this purpose. Different modes require different excitation power supplies. One mode requires AC three-phase current in the exciter stator 124 and the other mode requires DC current in the exciter stator 124.

The dual function exciter stator works in conjunction with contactor 220 located in the ICC. By switching the contactor into place, the windings in the exciter stator are configured as AC three-phase windings during the start mode. In this mode, exciter stator 124 with an AC three-phase winding and exciter rotor 122 with another AC three-phase form an inductive exciter. The direction of the phase sequence of the AC three-phase winding is opposite to the direction of the machine axis, controlled by an exciter digital control assembly 240 in the ICC. Thus, the induction exciter operates in its braking mode. In the generating mode, the windings in the exciter stator 124 are configured as DC windings. An exciter stator 124 with DC windings and an exciter rotor 122 with AC three-phase windings form a synchronous exciter. The AC and DC windings are configured to generate the necessary rotating fields in the air gap between exciter rotor 122 and exciter stator 124 during start-up and generate modes, respectively, without adding any size or weight to the exciter. In addition, during start-up mode, the AC windings transfer power from the exciter stator 124 to the exciter rotor 122.

In both the start-up mode and the generate mode, mechanical position information of main rotor 114 for power switch commutation is required each time the IGBTs 215 of main IGBT/diode bridge 210 commutate (communtate). As shown in fig. 2 and in detail in fig. 3 and 4, by the masterDigital control assembly 230 generates sensorless rotor position signals θ, ω_e(rotor position, rotor speed). The rotor position signal is formed by embedded software in the main digital control assembly 230 via the voltage and current signals of the S/G.

Fig. 3 shows a block diagram of the S/G and ICC system 50 in start-up mode. There are three motors-a main synchronous motor 110, an induction exciter 120 and a PMG 130. The main synchronous motor 110 and the induction exciter 120 play an important role in the start-up mode. The main IGBT/diode bridge 210 receives DC input power (e.g., 270VDC) from the DC bus and inverts the DC power to AC power. The three-phase AC current generated by the inverter is fed to the main synchronous motor 110. The gating signal that generates the AC current is controlled by the starter inverter digital control assembly 230. The starter inverter digital control assembly 230 measures a-phase current, b-phase current and DC bus voltage. The a-phase and b-phase currents are converted to alpha and beta currents in a synchronous stationary frame (frame) using Clarke transformation implemented by embedded software in the main digital control component 230. The a axis coincides with the a axis located at the center of the a-phase winding of the main stator, while the β axis is spatially 90 electrical degrees ahead of the a axis. The alpha and beta currents are further converted to d and q currents in a synchronous rotating coordinate system by using Park transformations implemented by the same embedded software. The d-axis is aligned with the axis of the excitation winding of main rotor 114, while the q-axis is spatially 90 electrical degrees ahead of the d-axis.

As shown in fig. 3, there are two current regulation loops-d and q-loop. The outputs of the d and q loops are d and q voltages that are converted back to alpha and beta voltages by using the Inverse-Park transform before being fed into Space Vector Pulse Width Modulation (SVPWM). To perform the Park and Inverse-Park transforms, the main rotor position angle is determined. The alpha and beta voltages are inputs to the SVPWM, which generates the gate control signals for the IGBT switches. The switching frequency may be set to 14kHz, or to some other suitable frequency.

As shown in fig. 3, similar to the starter inverter digital control component 230, the exciter inverter digital control component 240 also has Clarke, Park and Inverse-Park transformations. Likewise, the exciter inverter digital control assembly 240 has d and q current regulation loops. The gating signals are generated by their respective SVPWM. As previously described, because the fundamental frequency of the exciter IGBT/diode bridge 212 or exciter inverter is fixed at 1250Hz or some other suitable frequency, and the exciter 120 has no convexity (saliency) on its rotor 122 and stator 124, the rotor position information can be artificially constructed using the equation 2 pi ft, where f is 1250Hz and t is time. This is in contrast to the main inverter, i.e. in this case no real-time rotor position information is required. In one possible implementation, the SVPWM switching frequency of the exciter inverter is 10hz, such that other appropriately selected switching frequencies may be utilized while remaining within the spirit and scope of the present disclosure.

In a second embodiment in the start-up mode, the exciter 120 is configured as an induction machine that operates in its braking mode, or alternatively described, the exciter 120 functions like a three-phase resolver. The three-phase windings of exciter stator 124 generate a rotating field that induces three-phase voltages in exciter rotor 122. The direction of the rotating field is controlled to be opposite to the rotating direction of the main machine 110. Thus, during the start-up mode, the frequency of the voltage in exciter rotor 122 increases with rotor speed. DC power from an external power source is converted to three-phase 1250Hz power (or some other suitable frequency) by exciter IGBT/diode bridge 212. The electrical power passes through the air gap and is transferred to the windings of exciter rotor 122. The three-phase voltage is then rectified by a rotating rectifier 116 inside the rotor shaft of the main generator. The rectified voltage provides excitation power to rotor 114 of host 110. Once the rotor speed reaches the engine idle speed, the start mode is terminated and the generate mode is initiated. Exciter rotor 122 receives energy from exciter stator 124 and rotor shaft 118. At zero speed, all energy comes from the exciter stator 124. The energy from the shaft 118 increases as the rotor speed increases.

The sensorless implementation for constructing the main rotor position information through the digital control assembly 230 along with its embedded software includes two parts: a) high frequency injection sensorless estimation, and b) voltage mode sensorless estimation. The high frequency injection sensorless estimate covers from 0rpm to a predefined low speed, e.g. 80 rpm. The voltage mode sensorless estimate covers from a speed of, for example, 80rpm to a high speed (e.g., 14,400rpm) at which the engine is pulled to its cutoff speed. Most other sensorless approaches (including the voltage mode sensorless described above) fail at both zero and low speeds because these approaches are fundamentally dependent on back EMF. The high frequency injection method does not depend on back EMF. Thus, the method is applicable at speeds from 0 to a predefined low speed (e.g. 80 rpm). Thus, rotor position estimation at rpm and low speed of the main synchronous machine is achieved. A practical implementation of the sensorless is described below.

As shown in FIG. 3, when the speed of the main body 110 is lower than 80rpm or the frequency f of the main body 110₀<When 8Hz, a pair of 500Hz sine wave voltages V_αi，V_βiSuperimposed on the input of SVPWM. This 500Hz frequency is referred to as the carrier frequency. Other suitable carrier frequencies may be utilized while remaining within the spirit and scope of the present disclosure. In fig. 3, the carrier frequency is represented by the symbol ω_cAnd (4) showing. The response of the current in each phase to the two superimposed voltages contains rotor position information.

Each phase current of the main stator has multiple components. As shown in fig. 3, phase a and phase b currents are transferred to the α and β axes through Clarke transformation. The alpha and beta currents contain a frequency of omega_rFundamental component of frequency ω_cPositive sequence component of frequency 2 omega_r-ω_cThe negative sequence component of (a). Positive sequence component omega_cNo rotor position information is included. Therefore, this component is completely removed. As shown in FIG. 3, the alpha and beta currents are rotated by-omega_cAnd (5) t degree. Thus, the positive sequence component becomes a DC signal, which is then cancelled by using a second order high pass filter or some other type of high pass filter (e.g., first or third or higher order). The remaining components (i.e., the fundamental frequency component and the negative sequence component) contain rotor information. However, the rotor position is determined before the fundamental current is applied to the machine at zero speed, and at zero and low speeds, the fundamental component is very weak. The component capable of reliably extracting the rotor position information is a negative sequence component. After the previous rotation, the frequency of the component becomes 2 ω_r-2ω_c. Then the group is controlled by the numberMember 230 makes another rotation 2 omega_ct. The output of the rotation is passed through a 6 th order low pass filter, or to some other suitable low pass filter (e.g., a 1 st, 2 nd,.. or 5 th order low pass filter). By i_β2θResidual signal representing beta current, using i_α2θThe residual signal, representing the alpha current, yields the following angles:

unfortunately, the above angles are twice as frequent as the fundamental frequency and therefore cannot be used directly for Park and Inverse-Park transforms. In order to convert the above-described angle into a rotor position angle, it is detected whether θ' is under the north-to-south pole region or under the south-to-north pole region. If θ' is below the North-south region, then the angle is

θ＝θ′，

And if θ' is below the south to north pole region, the angle is

θ＝θ′+π。

This angle is then utilized in the Park and Inverse-Park transformations in the d and q current regulation loops. As shown in fig. 3, a band-stop filter (such as the 500Hz filter shown in fig. 3, whereby other stop band frequencies may be utilized while remaining within the spirit and scope of the present disclosure) is placed between the Clarke and Park transforms to eliminate carrier frequency interference on the d and q current regulation loops.

The high frequency injection sensorless approach works satisfactorily at zero or low speed. However, this method is not suitable for speeds where the frequency is close to or above the carrier frequency. Thus, when the speed exceeds a certain threshold rotational speed (e.g., 80rpm), another sensorless approach will be utilized. As described below, the method is a voltage mode sensorless method.

Voltage mode sensorless is achieved in the following way. Although this method has been used in induction motors and PM motors, it has not been applied to salient pole synchronous machines because the stator self-inductance is not a constant, but the inductance is a function of the rotor position. For reversal of the beta flux linkage through the alpha axis flux linkageThe conventional alpha and beta flux linkage equations in the synchronous stationary frame that are cut to generate the rotor angle are not applicable to salient wound field synchronous machines because the inductance is constantly changing. To overcome this problem, in a second embodiment, a pair of artificial flux linkages λ are derived_α' and λ_β' and their expressions:

wherein R is_sAnd L_qRespectively, a main stator resistor and a q-axis synchronous inductor. Both machine parameters are constant. Fortunately, λ_α' and λ_β' aligned with the alpha and beta flux linkages, respectively, and angled

θ＝tan^-1(λ′_β/λ′_α)

In effect, the rotor angle, which can be used for Park and Inverse-Park transformations once the machine speed is above a threshold rotational speed (e.g., above 80 rpm). These formulas may be implemented in the embedded software of the digital control component 230. This method provides a reliable rotor position angle estimation when the machine speed is above a certain rotational speed (e.g. above 80 rpm).

The combination of the two separate methods, high frequency injection sensorless and voltage mode sensorless, can provide rotor position information with sufficient accuracy over the entire speed range of synchronous machine-based starters.

During startup, the voltage applied by the main inverter on the main machine 110 is proportional to the speed and matches the vector sum of the back EMF and the voltage drop across the internal impedance of the main machine 110. The maximum voltage that the inverter can apply is the DC bus voltage. Once the vector sum equals the DC bus voltage, the inverter voltage saturates. Once saturation occurs, the speed of the host 110 can no longer rise and the d and q current regulation loops will run away. Typically, the inverter will over-current and shut down. The main digital control assembly 230 measures a line-to-line voltage V sent to an actuator digital control assembly 240_abAnd V_bc. Applying Clarke transformation to bothThe individual line-to-line voltages. The vector sum of the two outputs of the transform is used as feedback for an automatic field weakening loop, as shown in fig. 3. The DC bus voltage is factored and used as a reference for the control loop. The automatic field weakening control loop prevents inverter voltage saturation, thereby preventing the main inverter current regulation loop from running away and shutting down.

Automatic field weakening can be combined with near unity power factor (near unity power factor) control schemes to achieve higher power densities at high speed while the inverter voltage is saturated. By way of example and not limitation, near unity corresponds to a power factor greater than or equal to 0.9 and less than 1.0. While the automatic field weakening maintains the airgap field, a predetermined d-axis current profile (profile) is applied that urges the host 110 to operate in a region near unity power factor. As can be seen from the following equation, due to the automatic field weakening, in addition to the term ω L_md(i_f+i_d) Remains persistent and significant, term ω L_mqi_di_qAlso becomes significant. This significantly improves the power density of the S/G:

P＝ωL_md(i_f+i_d)i_q-ωL_mqi_di_q,

where P and ω are the electromechanical power and rotor speed, respectively, and L_mdAnd L_mqRespectively d and q magnetizing inductances.

The torque density at speeds lower than the base speed can be increased. As previously described, there are two current regulation loops in the main inverter digital control assembly 230. One is a d-axis loop and the other is a q-axis loop. Typically, the q-loop controls the generation of torque, while the d-loop controls the field in the air gap. This method is also called a vector control method. To obtain a high torque density, by applying a sufficient rotor excitation current i_fAnd a torque generating current i_qTo drive the magnetic saturation region of the machine. However, after the current reaches a certain level, regardless of the current i_q，i_dAnd i_qHow large the torque increases, the torque remains unchanged because the machine is magnetically saturated. The remedy is to maximize the reluctance torque of the machine with a vector control set. Machine generated machineThe electric torque is:

T＝L_md(i_f+i_d)i_q-L_mqi_di_q,

wherein L is_mdAnd L_mqRespectively d and q magnetizing inductances. Term L once the machine is magnetically saturated_md(i_f+i_d) Will become constant. Therefore, the method of generating reluctance torque is to apply negative id to the machine. Knowing i_dI sin δ and I_qThe above formula is optimized to obtain the optimal curve of id current:

wherein λ is_iIs the internal flux linkage of the machine.

Based on simulations performed by the inventors, by applying i at the input of the vector control_dThe curve can achieve a torque increase of about 38%. Overall, the appropriate i is controlled and obtained by the set vector_dThe current profile, the torque density of the machine will increase greatly.

In the third embodiment, the configuration and control of the ICC which achieves the maximum power generation efficiency are applicable to the power generation mode of the S/G and ICC system 50.

In the generating mode, as shown in fig. 2, the main machine 110 becomes a synchronous generator, and the exciter 120 becomes a synchronous generator. As shown, PMG 130 provides power to the exciter converter through a rectifier bridge. The exciter converter comprises two active IGBT/diode switches in an exciter IGBT/diode bridge 212, as shown in fig. 4. IGBT/diode switches with solid lines at the gate are used for the exciter converter. They are IGBT switch No. 1 and IGBT switch No. 4. During the generating mode, IGBT 1 is in the PWM mode, while IGBT 4 is always on. The remaining other IGBTs are all turned off. Diode No. 2 is used for freewheeling. IGBT 1, IGBT 4 and diode 2 plus the exciter stator winding form a buck converter that steps down the DC bus voltage (e.g., 270VDC) to a voltage that generates the desired excitation current for the synchronous exciter.

Passive and active rectification are configurable. Depending on the application, the main IGBT/diode bridge may become a passive rectifier or an active rectifier, controlled by the exciter converter digital control assembly 240 and the main converter digital control assembly 230. For applications where power flow is only in a single direction, the IGBT/diode bridge is constructed as a diode-operated bridge from main converter digital control assembly 230. For applications where power flow is bidirectional, the IGBT/diode bridge is constructed from the same digital control assembly as the IGBT and diode operating bridge. The S/G and ICC systems are in generating mode when the power flow direction is from ICC to the load. When the power flow direction is from load to ICC, the system is in a so-called regenerative mode, which is actually a motorizing mode. In passive rectification, only the intrinsic diodes in the IGBT switches of the main inverter (also called main IGBT/diode bridge) are used. The voltage regulation is done by embedded software in the exciter digital control assembly 240 and the generator converter digital control assembly 230 keeps the IGBTs in the main inverter off as shown in fig. 4. There are three control loops that control the POR voltage. The innermost one is the current regulator. The measured excitation current is feedback and the output of the AC voltage regulator is a reference. The current regulator controls the excitation current at a command level. The next loop is an AC voltage loop. As shown in FIG. 4, the feedback signal is max { | V_ab|,|V_bc|,|V_caAnd l. The reference is the output of the DC voltage regulator. The AC voltage loop plays an important role in keeping the DC voltage at the regulation Point (POR) within a desired range during load-off transients. The last control loop is a DC voltage loop. The voltage measured at POR is compared to a reference voltage of 270 VDC. The error enters a compensation regulator in the corresponding digital controller. Thus, the DC voltage of POR is regulated.

As previously described, for power generation applications requiring regeneration, the main IGBT/diode bridge is configured as an active rectifier. In such a configuration, voltage regulation is achieved by the following. As shown in fig. 4, the embedded codes in the exciter digital control assembly and the main digital control assembly are constructed differently from the codes of the passive rectification. Control of the exciter sideTherefore, the excitation current loop only becomes the PI control loop. The reference for the control loop is generated by a look-up table that is a function of the DC load current. The table is generated in such a way that the current in the main stator is close to its minimum possible value. The control on the primary side outer control loop is a DC voltage loop. The reference is 270 VDC; the feedback signal is a POR voltage. As shown in fig. 4, the control loop is a PI controller, where a feed forward of the DC output power is added to the output of the PI controller. The DC output power is equal to the product of the DC output current and the POR voltage. The sum of the feed forward signal and the output of the PI controller is the power command, which is used as a reference for the internal control loop (which is also the PI controller). The feedback signal is the power calculated by using the voltage and current of the generator, as shown in fig. 4. The output of the inner control loop is a voltage angle thetav and is used to generate an SVPWM vector V_dA and V_q*. These two vectors are the input to the inverse Park transform. The output of the transformation is the input to SVPWM as shown in fig. 4.

Control of the IGBT converter can combine automatic field modification and overmodulation to achieve optimal efficiency for IGBT power generation mode operation.

As shown in FIG. 4, V_dA and V_qIs calculated by the following formula:

V_d*＝|V*|sinθ_v

V_q*＝|V*|cosθ_v

wherein | V | ═ Vmag.

To optimize efficiency, first Vmag is chosen to be 1pu, forcing the converter into the full overmodulation region and fully reducing (dropping) the IGBT switching caused by SVPWM. This minimizes IGBT switching losses. IGBTs function like phase-shifted switches.

Because Vmag is a constant, the power loop regulates power by regulating the angle θ v. When the load is zero, θ v approaches zero, and when the load increases, θ v increases.

The second factor to achieve optimal efficiency is to optimize the actuator field current such that i_dThe current is minimized. Thus, the conduction losses of the IGBT and the copper losses of the generator are minimized. Discovery laserThe exciter field current is directly related to the DC load current. The higher the DC load current, the higher the required exciter field current. To achieve the minimum actuator field current, a look-up table is generated by measurement. The input to the look-up table is the DC load current and the output of the look-up table is a command for the actuator field current of the actuator stator. The table is generated in the following way: for each DC load current point, when i_dThe best exciter field current is found when the current is minimal. This control method not only achieves the best efficiency of the S/G and ICC system, but also provides an efficient method so that the operating point can be easily swung from the generation mode to the regeneration mode, i.e. motoring mode. Hereby, it is achieved that the surplus energy on the DC bus is sent back to the generator in the fastest way. A third aspect of the third embodiment relates to providing an IGBT commutation method during the generating mode. The commutation of the IGBT is based on a sensorless voltage mode, which is a similar sensorless approach used in start-up mode. However, since the operation mode is changed between the diode-only mode and the IGBT mode, the rotor position angle is determined before entering the IGBT mode. V_αAnd V_βObtained directly from the line-to-line voltage measurement, rather than from the SVPWM command.

Regeneration may be accomplished by absorbing excess energy on the DC bus into the machine while simultaneously regulating the bus voltage. During the generating mode, the load may generate excess energy. This excess energy can raise the DC bus voltage. This energy can be absorbed by the machine through the regeneration method provided by the overmodulation SVPWM of the present disclosure. In this case, the main inverter digital control reverses the direction of the voltage angle θ v and forces the main IGBT/diode bridge into motoring mode. Thus, the direction of power flow will be reversed. Power will flow from the load into the machine. Overmodulation prevents switching of the IGBT, thereby minimizing switching losses. This aspect of the disclosure provides a fast way to swing the main IGBT/diode bridge from generating mode to regenerating mode and vice versa.

Other aspects of the disclosure are contemplated in the subject matter of the present disclosure as well as configurations in the foregoing environments. For example, fig. 6 shows a fourth embodiment. The fourth embodiment has similar elements to the first, second and third embodiments; therefore, like parts will be identified with like numerals, and it is to be understood that the description of the like parts of the first, second and third embodiments applies to the fourth embodiment, unless otherwise specified.

One difference between the previous embodiment and the fourth embodiment is that the contactor 220 is not present in the fourth embodiment. As described herein, an alternative embodiment of the present disclosure may include a contactor 220.

As shown, another difference between the previous embodiment and the fourth embodiment is that the fourth embodiment replaces the IGBT/diode bridge of each of the exciter 120 and the host 110 with a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) based bridge configuration (shown as host MOSFET bridge 310 and exciter MOSFET bridge 312). Each respective MOSFET bridge 310 includes an array of independently controllable MOSFET devices 314, and each device 314 can optionally be configured to include an external diode configured across the MOSFET body diode in addition to the MOSFET body diode. Alternatively, embodiments of the present disclosure can eliminate the external diode for wide bandgap MOSFET devices 314 because the devices 314 have undesirable body diode electrical characteristics (e.g., higher power loss). Host MOSFET bridge 310 is communicatively coupled to and controllable by host digital control assembly 330. Likewise, driver MOSFET bridge 312 is communicatively coupled to and controllable by driver digital control assembly 340.

Each MOSFET 314 or each MOSFET bridge 310, 312 may include one or more solid state switches or wide bandgap devices, such as high bandwidth power switching MOSFETs based on silicon carbide (SiC) or gallium nitride (GaN). SiC or GaN can be selected based on their solid state material structure, their ability to handle high power levels in smaller and lighter form factors, and their ability to switch at high speeds for very fast electrical operation. Other wide bandgap devices or solid state material devices may be included.

Each of the digital control assemblies 330, 340 is shown coupled to each MOSFET 314 gate of a respective MOSFET bridge 310, 312, and operates according to the various modes described herein to control or drive each respective bridge 310, 312. For example, as described above, the host digital control assembly 330 and its embedded software may control the host MOSFET bridge 310, which host MOSFET bridge 310(1) generates AC power to drive the S/G100 in a start mode to start the prime mover of the aircraft, and (2) converts AC power obtained from the starter/generator 100 after the prime mover has been started to DC power in a generate mode of the starter/generator 100, as described above. During operation of the fourth embodiment, the host digital control assembly 330 may controllably operate the host bridge 310 to switch the control method from the start mode to the generate mode after the prime mover of the aircraft is started.

In one example, host MOSFET bridge 310 and host digital control assembly 330 can be configured to drive bridge 310 using SVPWM during a start-up mode, as described herein. As used herein, "driving" the MOSFET bridge may include operating a gate control or switching mode according to an example control method such as SVPWM. Additional switching patterns are also possible.

In another example, host MOSFET bridge 310 and host digital control component 330 can be configured to drive bridge 310 during generate mode using a reverse conduction based passive rectification method. An example of passive rectification based on reverse conduction has been shown in the simplified circuit shown in fig. 7. In the first circuit 400, a single phase current is shown passing through a first MOSFET 402 having an active gate by conducting current in the reverse direction (i.e., conducting current in the MOSFET channel in a direction from the source terminal to the drain terminal) (e.g., current passing through the MOSFET channel rather than the body diode). The current further passes through the electrical load 404 and returns through a second MOSFET 406 having an active gate, also conducting in reverse. The first circuit 400 also shows a third MOSFET 408 having a passive gate (e.g., not conducting via the MOSFET channel).

A second circuit 410 illustrates a first controllable switching event in which each of the second MOSFET 406 and the third MOSFET 408 is shown with a passive gate and a return current is conducted through each respective MOSFET 406, 408 body diode. During the first controllable switching event of the second circuit 410, the current shown commutates from the second MOSFET 406 to the third MOSFET 408. The third circuit 420 illustrates a second controllable switching event, where the third MOSFET 408 is shown as having an active gate and conducting current back through the MOSFET channel. In the third circuit 420, neither the second MOSFET 406 nor the third MOSFET 408 conduct current via the respective body diodes.

Although fig. 7 shows only single-phase controllable switching events, the reverse conduction based method of passive rectification may be used to control a MOSFET bridge (via MOSFET gate control and timing) to provide three-phase AC power rectification to DC power, as described herein.

In yet another example, the host digital control component 330 and its embedded software may control the host MOSFET bridge 310 such that the bridge 310 generates AC power to drive the S/G100 in an electric mode to drive or move the prime mover of the aircraft for testing or diagnostics of the S/G100 or the prime mover. In this example, host MOSFET bridge 310 and host digital control assembly 330 can be configured to operate or drive bridge 310 during motoring mode using SVPWM, as described herein.

Thus, host MOSFET bridge 310 can controllably invert or convert power as controlled by host digital control component 330. Although only the operation of host MOSFET bridge 310 is described, other aspects of the present disclosure may include similar operation of driver MOSFET bridge 312, where driver MOSFET bridge 312 is controllably operated by driver digital control assembly 340 to drive driver MOSFET bridge 312 during a generate mode using SVPWM. As with the previous aspects of the disclosure, although bidirectional power flow (i.e., starter/generator 100) is described, aspects of the disclosure may include unidirectional power flow, such as a generator. In addition, additional components (e.g., a host MOSFET bridge 310 Digital Signal Processor (DSP)) may be included to provide input related to the timing or method operation of the host digital control assembly 330, for example, by sensing or predicting starter/generator 100 rotor position.

Aspects of the present disclosure may further be configured such that the host MOSFET bridge 310 absorbs excess electrical energy of the aircraft power system by, for example, operating the host digital control component 330 to control the host MOSFET bridge 310 such that the excess energy is stored in kinetic energy of the rotor or prime mover of the aircraft, and wherein the host bridge gate driver operates to drive the MOSFET-based host bridge using space vector pulse width modulation during the regeneration mode.

In a fifth embodiment, as shown in fig. 8, the starter/generator 100 may further include a load balancing unit (LLU)450, the load balancing unit 450 selectively coupled with the DC power output 452 of the host 110 or ICC 200. The LLU 450 can include, for example, an integrated redundant regenerative power conversion system with a power storage device 470, such as a battery, fuel cell, or supercapacitor. The LLU 450 can be configured to operate such that during periods of excess power (e.g., when excess energy is returned from the aircraft electrical flight control actuation or excess power generation from the starter/generator 100), electrical energy of the aircraft power system is selectively absorbed or received by the power storage device 470 (i.e., "receive mode"). The LLU 450 can be further configured to operate such that electrical energy of the electrical power storage device 470 is supplied during peak power or under-generation (e.g., during engine start-up or high power system demand (such as flight control actuation)) (i.e., "supply mode").

As shown, the LLU 450 can include an inverter/converter/controller, such as a LLU MOSFET-based bridge 480 similar to the host MOSFET bridge 310 described herein, and whose output is selectively connected in parallel with the DC output of the starter/generator 100. The LLU digital control assembly 460 can be included and configured to selectively drive the LLU MOSFET bridge 480 during various modes of operation. For example, when the LLU 450 is operating to supply DC power to the DC power output of the starter/generator 100 during the supply mode, the LLU digital control component 460 can operate the gates of the LLU MOSFET bridge 480 by utilizing a Pulse Width Modulation (PWM) method. As described herein, the LLU 450 can operate in a supply mode to provide power to the host MOSFET bridge 310 to operate in a start-up or motoring mode. In another example, when the LLU 450 is operating to receive DC power from the DC power output of the starter/generator during the receive mode, the LLU digital control component 460 can operate the gates of the LLU MOSFET bridge 480 by utilizing a PWM method.

As described herein, the LLU 450 can operate in a receive mode to absorb power from the host MOSFET bridge 310 when operating in a generate mode. In this sense, the LLU 450 can operate to discharge to the aircraft electrical system, as well as charge from excess power on the aircraft electrical system. This embodiment may be further configured such that, in the event of a LLU 450 failure, the host MOSFET bridge 310 absorbs excess electrical energy of the aircraft power system, for example, by operating the host digital control component 330 to control the host MOSFET bridge 310 such that the excess energy is stored in the kinetic energy of the rotor or prime mover of the aircraft, and wherein the host bridge gate driver operates to drive the MOSFET-based host bridge using space vector pulse width modulation during the regeneration mode. As with the above disclosed aspects, each respective MOSFET bridge 310, 312, 480 includes an array of independently controllable MOSFET devices 314, and each device 314 can optionally be configured to include, in addition to a MOSFET body diode, an external diode configured across the MOSFET body diode.

In yet another example embodiment, as shown in fig. 9, the starter/generator 100 may further include a four-arm inverter 550 coupled to the DC power output 452 of the host 110 or ICC 200. The four-arm inverter 550 may operate in a generate mode to convert DC power received from the DC power output 452 of the host 110 or ICC 200 to AC power, and may further operate in a start mode to generate and provide DC power to drive the starter/generators to start the prime movers of the aircraft.

As shown, the four-leg inverter/converter 550 may include an inverter/converter/controller, such as a MOSFET-based four-leg bridge 580, similar to the host MOSFET bridge 310 described herein, and configured to have three outputs 582 for three different phases of the AC power, and a fourth output 584 for a neutral output, relative to the three phases of the AC power. In one example, the three-phase AC output may be 400 Hz. Embodiments may further include a four-arm digital control assembly 560, the four-arm digital control assembly 560 configured to selectively drive a four-arm MOSFET bridge 580 during various operating modes. For example, when the four-leg inverter/converter 550 is operating during the generate mode to convert DC power from the DC power output 452 to three-phase (and neutral) AC power, the four-leg digital control assembly 560 may invert the DC power from the DC power output 452 to AC power, for example, by operating the gates of the four-leg MOSFET bridge 580 with a PWM method. As described herein, the quad inverter/converter 550 may also operate in a start-up mode to provide power to the main machine MOSFET bridge 310 to operate in a start-up or motoring mode by, for example, operating the gates of the quad MOSFET bridge 580 using a PWM method to actively rectify AC power to DC power provided to the DC power output 452.

Embodiments may also be configured such that the host MOSFET bridge 310 absorbs excess electrical energy of the aircraft power system by, for example, operating the host digital control assembly 330 to control the host MOSFET bridge 310 such that the excess energy is stored in kinetic energy of the rotor or prime mover of the aircraft, and wherein the host bridge gate driver operates to drive the MOSFET-based host bridge using space vector pulse width modulation during the regeneration mode. As with the embodiments of the present disclosure described above, each respective MOSFET bridge 310, 312, 580 includes an array of independently controllable MOSFET devices 314, and each device 314 can optionally be configured to include, in addition to a MOSFET body diode, an external diode configured across the MOSFET body diode.

Additional aspects of the present disclosure contemplate alternative iterations of the MOSFET-based bridge described herein. For example, one embodiment of the present disclosure can have driver MOSFET bridge 312 and LLU MOSFET bridge 480. Another aspect of the present disclosure may have a host MOSFET bridge 310 and a four-arm MOSFET bridge 580. Yet another aspect of the present disclosure may have only a host MOSFET bridge 310. Further, any of the MOSFET bridges described herein may operate under alternative or varying control methods, and may include similar or dissimilar materials or solid state devices. In addition, the design and placement of the various components can be rearranged such that many different in-line configurations can be achieved.

Fig. 10 shows an example cross-sectional view of another starting and generating system 650, the starting and generating system 650 including an induction generator 651 having a main machine 110 and a PMG 130. As shown, the PMG 130 also includes a PMG rotor 133 and a PMG stator 131. For example, the starting and generating system 650 shown in fig. 10 includes similar elements to previously described aspects of the present disclosure; therefore, like parts will be identified with like numerals, and it should be understood that the description of the like parts of the first, second, and third examples applies to the fourth example unless otherwise specified.

One difference between the previous example and the starting and generating system 650 of fig. 10 is that the starting and generating system 650 includes an induction generator 651 assembly, arrangement or configuration. As used herein, the induction generator 651 may comprise a starter/generator assembly configuration in which current is induced at the main machine 110, such as by the PMG 130, as opposed to using an exciter assembly, a rotating rectifier, or the like. As shown, the PMG rotor 133 and the host rotor 114 may be rotatably connected by a rotatable shaft 618.

As shown in fig. 11, the starting and generating system 650 includes an induction generator. The starting and generating system 650 includes similar elements as previously described aspects of the present disclosure; accordingly, like parts will be identified with like numerals, it being understood that the description of like parts of the previously described examples applies to the starting and generating system 650, unless otherwise noted. As shown, one non-limiting difference between the previous aspect and the starting and generating system 650 is that the IGBT/diode bridge of the host 110 is replaced with a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) based bridge structure (shown as host MOSFET bridge 610 comprising an array of independently controllable MOSFET devices 614). In addition to the MOSFET body diode, each device 614 may optionally be configured to include an external diode configured across the MOSFET body diode. Alternatively, because the device 614 has undesirable body diode electrical characteristics (e.g., higher power loss), aspects of the present disclosure may enable elimination of an external diode for the wide bandgap MOSFET device 614. Host MOSFET bridge 610 is communicatively coupled to and controlled by host digital control assembly 630.

Each MOSFET614 or each MOSFET bridge 610 may include one or more solid state switches or wide bandgap devices, such as high bandwidth power switching MOSFETs based on silicon carbide (SiC) or gallium nitride (GaN). SiC or GaN can be selected based on their solid state material structure, their ability to handle high power levels in smaller and lighter form factors, and their ability to switch at high speeds for very fast electrical operation. Other wide bandgap devices or solid state material devices may be included.

In yet another example aspect of the present disclosure, the starting and generating system 650 may further include a four-arm inverter 550, the four-arm inverter 550 coupled with the DC power output 652 of the host 110 or the host MOSFET bridge 610. Host digital control assembly 630 is shown coupled to the gate of each MOSFET614 of MOSFET bridge 610 through bridge driver communication coupling 664, and operates according to the various modes described herein to control or drive each respective bridge 610 or MOSFET 614. The four-arm inverter 550 may operate in a generating mode to convert DC power received from the DC power output 652 of the main machine 110 or the main machine MOSFET bridge 610 to AC power, and may further operate in a starting mode to generate and provide DC power to drive the starter/generators to start the prime movers of the aircraft.

As shown, the four-leg inverter/converter 550 may include an inverter/converter/controller, such as a MOSFET-based four-leg bridge 580, similar to the host MOSFET bridges 310, 610 described herein, and configured to have three outputs 582 for three different phases of the AC power, and a fourth output 584 for a neutral output, relative to the three phases of the AC power. In one example, the three-phase AC output may be 400 Hz. Aspects of the present disclosure may further include a quad-arm digital control assembly 660, the quad-arm digital control assembly 660 configured to selectively drive a quad-arm MOSFET bridge 580 during various modes of operation, such as through a bridge driver communication coupling 662. For example, when quad inverter/converter 550 is operating during generate mode to convert DC power from DC power output 652 to three-phase (and neutral) AC power, quad digital control assembly 660 may operate the gates of quad MOSFET bridge 580 by utilizing a PWM method. The four-arm inverter/converter 550 may further operate in a start-up mode to provide power to the main machine MOSFET bridge 610 to operate in a start-up or motoring mode by operating the gates of the four-arm MOSFET bridge 580 using a PWM method, as described herein.

Aspects of the present disclosure may be further configured such that the host MOSFET bridge 610 absorbs excess electrical energy of the aircraft power system by, for example, operating the host digital control assembly 630 to control the host MOSFET bridge 610 such that the excess energy is stored in kinetic energy of the rotor or prime mover of the aircraft, and wherein the host digital control assembly 630 operates during a regeneration mode to drive the MOSFET-based host bridge 610, for example as an inverter to invert the power received at the power output 652 into AC power for driving the motion of the rotor. In one non-limiting example, the host bridge 610 can be operated by the host digital control component 630 using space vector pulse width modulation. As with the above disclosed aspects, each respective MOSFET bridge 610, 580 includes an array of independently controllable MOSFET devices 614, and each device 614 may optionally be configured to include, in addition to a MOSFET body diode, an external diode configured across the MOSFET body diode.

The host MOSFET bridge 610 may operate to generate power through induction generator operation. For example, the DC power input 666 of the host digital control component 630 may receive DC power from the PMG 130. The host digital control component 630 may then provide or otherwise selectively apply the power supply received at the power input 666 to the host 110 via the power output 668. Host 110 generates power by induction and supplies or provides the generated power to host MOSFET bridge 610. Host digital control assembly 630 controllably operates host MOSFET bridge 610 through bridge driver communication coupling 664 and operates to control or drive each respective bridge 310 or MOSFET614 according to the various modes described herein (e.g., by actively rectifying multi-phase power to DC power delivered to DC power output 652). In a further non-limiting aspect of the present disclosure, the host digital control component 630 may ensure proper, desired, or expected operation by receiving feedback (e.g., through a voltage sense input 672 adapted to sense or measure the voltage at the output of the host MOSFET bridge 610).

The output of host MOSFET bridge 610 can further be provided to MOSFET-based quad-arm bridge 580 and can operate as described herein. The MOSFET-based four-armed bridge 580 may further provide a four-phase power output 654.

Additional aspects of the present disclosure contemplate alternative iterations of the MOSFET-based bridge described herein. For example, one non-limiting aspect of the present disclosure may include a host MOSFET bridge 610 and a four-arm MOSFET bridge 580. Yet another aspect of the present disclosure may have only a host MOSFET bridge 610. Further, any of the MOSFET bridges described herein may operate under alternative or varying control methods, and may include similar or dissimilar materials or solid state devices. In addition, the design and placement of the various components can be rearranged such that many different in-line configurations can be achieved.

In yet another example aspect of the present disclosure, fig. 12 shows a block diagram of another starting and generating system 750, the starting and generating system 750 including an induction generator having a MOSFET-based main machine bridge, and configured to provide a HVDC power output. For example, the starting and generating system 750 shown in fig. 12 includes similar elements to previously described aspects of the present disclosure; accordingly, like parts will be identified with like numerals, it being understood that the description of like parts of the previously described examples applies to the starting and generating system 750, unless otherwise noted.

One difference between the previous example and the starting and generating system 750 of FIG. 12 is that the starting and generating system 750 includes an induction generator assembly, arrangement or configuration. As shown, another difference between the previous aspect and the starting and generating system 750 is the replacement of the IGBT/diode bridge of the main machine 110 with a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) based bridge configuration (shown as main machine MOSFET bridge 710 comprising an array of independently controllable MOSFET devices 714). In addition to the MOSFET body diode, each device 714 can optionally be configured to include an external diode configured across the MOSFET body diode. Alternatively, because the device 714 has undesirable body diode electrical characteristics (e.g., higher power loss), aspects of the present disclosure may enable elimination of an external diode for the wide bandgap MOSFET device 714. Host MOSFET bridge 710 is communicatively coupled to and controllable by host digital control assembly 730.

Each MOSFET 714 or each MOSFET bridge 710 may include one or more solid state switches or wide bandgap devices, such as high bandwidth power switching MOSFETs based on silicon carbide (SiC) or gallium nitride (GaN). SiC or GaN can be selected based on their solid state material structure, their ability to handle high power levels in smaller and lighter form factors, and their ability to switch at high speeds for very fast electrical operation. Other wide bandgap devices or solid state material devices may be included.

The illustrated digital control assembly 730 is coupled to the gate of each MOSFET 714 of the MOSFET bridge 310 via a bridge driver communication coupling 752 and operates according to the various modes described herein to control or drive each respective bridge 310 or MOSFET 714. For example, as described above, the host digital control assembly 730 and its embedded software may control the host MOSFET bridge 710, which host MOSFET bridge 710(1) generates AC power to drive the start and generation system 750 in a start mode to start the prime movers of the aircraft, and (2) converts AC power obtained from the start and generation system 750 after the prime movers have been started to DC power in a generation mode of the start and generation system 750. During operation of the start-up and power generation system 750, the host digital control assembly 730 may controllably operate the host bridge 710 to switch the control method from the start-up mode to the power generation mode after the prime mover of the aircraft is started.

As described herein, in one example, host MOSFET bridge 710 and host digital control assembly 730 can be configured to use SVPWM drive bridge 710 during a start-up mode. As used herein, "driving" the MOSFET bridge may include operating a gate control or switching mode according to an example control method such as SVPWM. Additional switching patterns are also possible.

In another example, host MOSFET bridge 710 and host digital control assembly 730 can be configured to drive bridge 710 during generate mode using a reverse conduction based passive rectification method. One example of reverse conduction based passive rectification has been shown in the simplified circuit shown in fig. 7 and explained with reference to fig. 7.

The main machine MOSFET bridge 710 may operate by induction generator operation to generate power. For example, DC power input 766 of host digital control component 730 may receive DC power from PMG 130. The host digital control assembly 730 may then supply, provide, or otherwise selectively apply the power received at the power input 766 to the host 110 via the power output 768. In this sense, PMG 130 may establish or otherwise supply an induced or initial voltage for main machine 110 of the induction generator. Host 110 generates power by induction and supplies or provides the generated power to host MOSFET bridge 710. Host digital control assembly 730 controllably operates host MOSFET bridge 710 through bridge driver communication coupling 752, as explained herein. In further non-limiting aspects of the present disclosure, the host digital control component 730 can ensure proper, desired or expected operation by receiving feedback, such as via a voltage sense input 772 adapted to sense or measure the voltage at the output of the host MOSFET bridge 710.

The starting and generating system 750 is also shown as including a DC power output 754. DC power output 754 can be included based on a set of independently controllable MOSFET devices 756, for example, forming a DC-to-DC ("DC/DC") converter MOSFET bridge 758. DC/DC converter MOSFET bridge 758 may be communicatively coupled to and controllable by DC/DC digital control assembly 770 via bridge driver communication coupling 762. The output of the DC/DC converter MOSFET bridge 758 may further be provided to, for example, a buck converter 764 constructed or adapted to step the DC bus voltage to a desired voltage, e.g., 270VDC, that generates a desired DC power output 754. In one non-limiting example, the desired DC power output may include a high voltage power output, such as 270 VDC.

Although the description of fig. 12 includes driving host MOSFET bridge 710 using SVPWM, additional or alternative bridge driving examples are contemplated. For example, when the starting and generating system 750 is operating to supply DC power to the DC power output during the supply mode, the host digital control component 730 controllably operates the gates of the host MOSFET bridge 710 by utilizing a Pulse Width Modulation (PWM) method. The starting and generating system 750 may further be operated in a receiving mode to absorb power from the main machine MOSFET bridge 710 when operating in a generating mode, as described herein. In this sense, the starting and generating system 750 may operate to discharge to the aircraft electrical system, as well as to charge from excess power on the aircraft electrical system. Aspects of the present disclosure may be further configured such that the main machine MOSFET bridge 710 absorbs excess electrical energy of the aircraft electrical system in the event of a failure of the starting and generating system 750 by, for example, operating the main machine digital control assembly 730 to control the main machine MOSFET bridge 710 such that the excess energy is stored in the kinetic energy of the rotor or prime mover of the aircraft, and wherein the main machine bridge gate driver operates to drive the MOSFET-based main machine bridge using space vector pulse width modulation during the regeneration mode.

Aspects disclosed herein provide aircraft starting and generating systems having MOSFET-based bridge configurations. One advantage that may be realized in the above aspect is that the above aspect implements a MOSFET-based controllable bridge that can perform inversion and conversion functions based on a control method or mode. For example, by using SVPWM for certain functions, the starter/generator can achieve synchronous gating while minimizing losses in the MOSFET-based bridge. Furthermore, when conducting current across the MOSFET device in the reverse direction of the reverse conduction based passive rectification, the power loss across the MOSFET may be lower than the power loss caused by the forward voltage drop in the diode, thereby further minimizing power loss.

In addition, the demand on the electrical systems of aircraft has increased with the rise of electronic flight control actuation compared to conventional flight control actuation. Furthermore, when the increased demand on the power system ceases due to electronic flight control actuation, the increase in available power from the power system threatens other sensitive electronic devices, which may be damaged by the electrical surge. The LLU incorporating the MOSFET-based gate control methods described herein provides supplemental power when electrical demand is high, and absorbs excess power when electrical demand is low.

Yet another advantage that may be realized in the above aspect is that the broadband gaming MOSFET device has the advantages of lower losses, higher switching frequency and higher operating temperature compared to conventional semiconductor devices. Furthermore, although body diodes are utilized during the control method and tend to have higher power losses than MOSFET operation alone, the use of such diodes is minimized, which in turn provides lower power losses for the electrical system.

Yet another advantage that may be realized in the above aspects is that these aspects have superior weight and size advantages as compared to starter/generators, exciters, LLUs and four-armed inverter/converter systems. Furthermore, solid state devices (e.g., MOSFET-based bridges) have lower failure rates and increased reliability. Important factors to be solved when designing aircraft components are size, weight and reliability. The resulting aspects of the present disclosure have lighter weight, smaller size, increased performance, and increased reliability systems. The reduction in weight and size is associated with a competitive advantage during flight.

The different features and structures of the various aspects may be used in combination with each other as desired, insofar as not described. A feature that cannot be shown in all aspects is not meant to be an explanation of it, but is done so for brevity of description. Thus, the various features of the different aspects can be mixed and matched as desired to form new aspects, whether or not such aspects are explicitly described. All combinations or permutations of features described herein are covered by this disclosure.

This written description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Further aspects of the invention are provided by the subject matter of the following clauses:

an aircraft starting and generating system comprising: a starter/generator comprising a main machine and a permanent magnet generator; a Direct Current (DC) power output from the starter/generator; a four-arm inverter coupled with the DC power output and having an inverter/converter/controller (ICC) with a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) based four-arm bridge configuration, and that generates DC power to drive the starter/generator in a start mode to start a prime mover of the aircraft, and that converts DC power obtained from the starter/generator after the prime mover has been started to Alternating Current (AC) power in a generate mode of the starter/generator; and a quad bridge gate driver configured to drive the MOSFET-based quad bridge, wherein the quad bridge gate driver operates using Pulse Width Modulation (PWM) to drive the MOSFET-based quad bridge during a start-up mode and a generation mode.

The aircraft starting and generating system of any preceding item, wherein the MOSFET-based four-armed bridge configuration further comprises three arms each having a single phase output of a three phase AC output, and a fourth arm having a neutral output.

The aircraft starting and generating system of any preceding item wherein the three-phase AC output is 400 Hz.

The aircraft starting and generating system of any preceding item, wherein the MOSFET-based four-armed bridge further comprises at least one of a silicon carbide-based bridge or a gallium nitride-based bridge.

The aircraft starting and generating system of any preceding item wherein the starter/generator is an induction generator.

The aircraft starting and generating system of any preceding item wherein the permanent magnet generator establishes an induced voltage for the induction generator.

The aircraft starting and generating system of any preceding item, further comprising: a MOSFET-based main machine bridge connected to a stator of a main machine; and a host bridge gate driver configured to drive the MOSFET-based host bridge.

An aircraft starting and generating system according to any preceding clause wherein the host machine comprises a MOSFET-based host machine bridge configuration that absorbs excess power of the system in a regeneration mode by storing the excess power in kinetic energy of the prime mover of the aircraft, and wherein the host machine bridge gate driver operates to drive the MOSFET-based host machine bridge using space vector pulse width modulation during a regeneration mode.

The aircraft starting and generating system of any preceding item, wherein the MOSFET-based host bridge further comprises at least one of a silicon carbide-based bridge or a gallium nitride-based bridge.

The aircraft starting and generating system of any preceding item wherein the MOSFET-based four-armed bridge further comprises an array of independently controllable MOSFETs.

The aircraft starting and generating system of any preceding item wherein the four-arm bridge gate driver operates to drive each independently controllable MOSFET.

The aircraft starting and generating system of any preceding item wherein the MOSFET-based four-armed bridge further comprises independently controllable wide bandgap device MOSFETs.

The aircraft starting and generating system of any preceding item wherein the MOSFET further comprises an external diode configured across the body diode of the MOSFET.

A method of controlling an aircraft starting and generating system having: an inductive starter/generator comprising a main machine having a DC power output and a permanent magnet generator; a four-arm converter coupled with the DC power output and having an inverter/converter/controller (ICC) with a MOSFET-based bridge configuration; and a four-arm bridge gate driver configured to drive a MOSFET-based bridge, the method comprising: supplying power to the MOSFET-based quadrifilar bridge if in a start mode and driving the MOSFET-based quadrifilar bridge using Pulse Width Modulation (PWM) during the start mode, and wherein driving the MOSFET-based main bridge during the start mode starts a prime mover of the aircraft; and if in generate mode, driving the MOSFET-based four-arm bridge using PWM to convert DC power obtained from the DC power output of the starter/generator to four-arm AC power.

The method of any preceding clause, further comprising: supplying power to the MOSFET-based quad-bridge if in motoring mode, and driving the MOSFET-based quad-bridge using PWM during start mode, and wherein driving the MOSFET-based main bridge during start mode rotates a prime mover of the aircraft.

The method of any preceding claim, further comprising performing a diagnostic test on at least one of the induction starter/generator or the prime mover.

The method of any preceding clause, further comprising: if in start mode, switching to generate power after starting the prime mover of the aircraft.

The method of any preceding item, wherein driving the MOSFET-based bridge further comprises converting the DC power to 400Hz AC power if in generate mode.

An aircraft, comprising: an engine; an induction starter/generator connected to the engine and having a main machine and a permanent magnet generator; a Direct Current (DC) power output from the inductive starter/generator; a four-arm inverter coupled with the DC power output and having an inverter/converter/controller (ICC) with a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) based four-arm bridge configuration and generating DC power to drive the starter/generator in a start mode to start the engine and converting DC power obtained from the starter/generator after the engine has been started to Alternating Current (AC) power in a generate mode of the induction starter/generator; and a quad-bridge gate driver configured to drive the MOSFET-based quad-bridge, wherein the quad-bridge gate driver is operative to drive the MOSFET-based quad-bridge using Pulse Width Modulation (PWM) during start-up and generate modes.

The aircraft of any preceding item, wherein the MOSFET-based four-armed bridge configuration further comprises three arms each having a single phase output of a three phase AC output, and a fourth arm having a neutral output.