阅读说明：本技术 多相永磁直流马达驱动器的前馈控制 (Feedforward control of multiphase permanent magnet DC motor drive ) 是由 P·普拉莫德 于 2020-11-30 设计创作，主要内容包括：本申请公开了多相永磁直流马达驱动器的前馈控制。用于控制永磁直流(PMDC)机器的输出转矩的系统和方法包括PMDC马达和控制器,该PMDC马达包括多组绕组。PMDC马达被配置为生成输出转矩。该控制器被配置为：对于PMDC马达的第一组绕组,基于第一输入转矩命令信号和该第一组绕组的反电动势电压降来确定第一电压命令；对于PMDC马达的第二组绕组,基于第二输入转矩命令信号来确定第二电压命令；以及根据第一电压命令和第二电压命令选择性地控制PMDC马达。(The application discloses feedforward control of a multiphase permanent magnet dc motor drive. A system and method for controlling an output torque of a Permanent Magnet Direct Current (PMDC) machine includes a PMDC motor including a plurality of sets of windings and a controller. The PMDC motor is configured to generate an output torque. The controller is configured to: for a first set of windings of the PMDC motor, determining a first voltage command based on a first input torque command signal and a back emf voltage drop of the first set of windings; determining, for a second set of windings of the PMDC motor, a second voltage command based on a second input torque command signal; and selectively controlling the PMDC motor according to the first voltage command and the second voltage command.)

1. A system for controlling output torque of a permanent magnet direct current PMDC machine, comprising:

a PMDC motor configured to generate the output torque, the PMDC motor including a plurality of sets of windings; and

a controller configured to:

determining, for a first set of windings of the PMDC motor, a first voltage command based on a first input torque command signal and a back-emf voltage drop of the first set of windings;

determining, for a second set of windings of the PMDC motor, a second voltage command based on a second input torque command signal; and

selectively controlling the PMDC motor according to the first voltage command and the second voltage command.

2. The system of claim 1, wherein the controller is further configured to determine the first voltage command based on a brush voltage drop of the first set of windings.

3. The system of claim 1, wherein the controller is further configured to determine the second voltage command using a brush voltage drop and a back-emf voltage drop of the second set of windings.

4. The system of claim 1, wherein the controller is further configured to determine the first voltage command based on an inductance of the circuitry of the PMDC motor and a resistance of the circuitry of the PMDC motor.

5. The system of claim 1, wherein the controller is further configured to determine the second voltage command based on an inductance of the circuitry of the PMDC motor and a resistance of the circuitry of the PMDC motor.

6. The system of claim 1, wherein the controller is further configured to:

determining a voltage value based on the first input torque command signal, an inductance of a circuit of the PMDC motor, and a resistance of the circuit of the PMDC motor; and

calculating a sum of the back-emf voltage drops and the voltage values for the first set of windings.

7. The system of claim 6, wherein the controller is further configured to determine the first voltage command based on the voltage value and a sum of the voltage value, a brush voltage drop of the first set of windings, and a back electromotive force voltage drop of the first set of windings.

8. The system of claim 1, wherein the controller is further configured to determine a back-emf voltage drop for the first set of windings using a motor speed signal estimate.

9. The system of claim 1, wherein the controller is further configured to:

applying the first voltage command to the first set of windings, the first set of windings generating a first current in response to the first voltage command; and

applying the second voltage command to the second set of windings, the second set of windings generating a second current in response to the second voltage command; wherein the PMDC motor generates an output torque in response to the first current and the second current.

10. The system of claim 1, wherein the controller is further configured to determine the first voltage command and the second voltage command using a mathematical transform.

11. A controller for controlling output torque of a multiphase permanent magnet direct current PMDC motor, the controller configured to:

determining, for a first set of windings of the multi-phase PMDC motor, a first voltage command based on a first input torque command signal and a back-emf voltage drop of the first set of windings;

determining, for a second set of windings of the multi-phase PMDC motor, a second voltage command based on a second input torque command signal; and

selectively controlling the multi-phase PMDC motor according to the first voltage command and the second voltage command.

12. The controller of claim 11, wherein the controller is further configured to determine the first voltage command based on a brush voltage drop of the first set of windings.

13. The controller of claim 11, wherein the controller is further configured to determine the second voltage command using a brush voltage drop and a back-emf voltage drop of the second set of windings.

14. The controller of claim 11, wherein the controller is further configured to determine the first voltage command based on an inductance of the circuit of the multi-phase PMDC motor and a resistance of the circuit of the multi-phase PMDC motor.

15. A method for controlling output torque of a multi-phase permanent magnet direct current PMDC motor, the method comprising:

determining, for a first set of windings of the multi-phase PMDC motor, a first voltage command based on a first input torque command signal and a back-emf voltage drop of the first set of windings;

determining, for a second set of windings of the multi-phase PMDC motor, a second voltage command based on a second input torque command signal; and

selectively controlling the multi-phase PMDC motor according to the first voltage command and the second voltage command.

16. The method of claim 15, further comprising determining the first voltage command based on a brush voltage drop of the first set of windings.

17. The method of claim 15, further comprising determining the second voltage command using a brush voltage drop and a back-emf voltage drop of the second set of windings.

18. The method of claim 15, further comprising: determining the first voltage command based on an inductance of a circuit of the multi-phase PMDC motor and a resistance of the circuit of the multi-phase PMDC motor.

19. The method of claim 15, further comprising: determining a back EMF voltage drop for the first set of windings using a motor speed signal estimate.

20. The method of claim 15, further comprising:

applying the first voltage command to the first set of windings, the first set of windings generating a first current in response to the first voltage command; and

applying the second voltage command to the second set of windings, the second set of windings generating a second current in response to the second voltage command; wherein the multi-phase PMDC motor generates an output torque in response to the first current and the second current.

Technical Field

The present disclosure relates to facilitating feed forward torque and current control of a multiphase permanent magnet dc motor.

Background

Permanent Magnet Direct Current (PMDC) motors (also known as brushed DC motors) are widely used in motion control applications, such as in Electric Power Steering (EPS) systems, power tools, and the like. PMDC motors with multiple sets of windings have been developed to provide redundancy in EPS applications. Although these motors are similar to their typical single winding counterparts (counters), most common winding schemes result in inductive coupling between different sets of windings. This results in the currents and thus the torques, control behavior of these motors being different from that of single winding motors. Therefore, existing control schemes cannot be extended to multi-phase PMDC motors.

The torque control of the PMDC motor drive is performed by current regulation (by a current measurement circuit) with measured current feedback. For example, feed forward current and torque control is one mode of controlling a PMDC motor drive. To achieve feed forward control of a PMDC motor, an accurate model of the PMDC motor is required (including non-linearities such as brush drop voltage).

Disclosure of Invention

The present disclosure relates generally to facilitating feed-forward torque and current control of a multi-phase Permanent Magnet Direct Current (PMDC) motor.

One aspect of the disclosed embodiments includes a system for controlling an output torque of a PMDC machine. The system includes a PMDC motor including a plurality of sets of windings and a controller. The PMDC motor is configured to generate an output torque. The controller is configured to: for a first set of windings of the PMDC motor, determining a first voltage command based on a first input torque command signal and a back-electromotive force (back-EMF) voltage drop (drop voltage) of the first set of windings; determining, for a second set of windings of the PMDC motor, a second voltage command based on the second input torque command signal; and selectively controlling the PMDC motor according to the first voltage command and the second voltage command.

Another aspect of the disclosed embodiments includes a controller for controlling an output torque of a PMDC motor. The controller is configured to: for a first set of windings of the multi-phase PMDC motor, determining a first voltage command based on the first input torque command signal and a back emf voltage drop across the first set of windings; determining, for a second set of windings of the multi-phase PMDC motor, a second voltage command based on the second input torque command signal; and selectively controlling the multi-phase PMDC motor according to the first voltage command and the second voltage command.

Another aspect of the disclosed embodiments includes a method for controlling output torque of a PMDC motor. The method comprises the following steps: for a first set of windings of the multi-phase PMDC motor, a first voltage command is determined based on a first input torque command signal and a back emf voltage drop of the first set of windings. The method further comprises the following steps: for a second set of windings of the multi-phase PMDC motor, a second voltage command is determined based on the second input torque command signal. The method further comprises the following steps: the multi-phase PMDC motor is selectively controlled according to the first voltage command and the second voltage command.

These and other aspects of the disclosure are disclosed in the following detailed description of the embodiments, the appended claims and the accompanying drawings.

Drawings

The present disclosure is best understood from the following detailed description when read with the accompanying drawing figures. It is emphasized that, according to common practice, the various features of the drawings are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity.

FIG. 1 generally illustrates a vehicle according to the principles of the present disclosure.

Fig. 2 generally illustrates an example multi-winding Permanent Magnet Direct Current (PMDC) machine according to principles of the present disclosure.

Fig. 3 generally illustrates a block diagram of a dual winding PMDC machine using a mathematical model in accordance with the principles of the present disclosure.

FIG. 4 generally illustrates a block diagram of a system for feed forward current and torque control according to the principles of the present disclosure.

FIG. 5 generally illustrates another block diagram of a system for feed forward current and torque control according to the principles of the present disclosure.

FIG. 6 is a flow chart generally illustrating a feed forward current and torque control method according to the principles of the present disclosure.

Detailed Description

The following discussion is directed to various embodiments of the invention. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment.

As mentioned above, Permanent Magnet Direct Current (PMDC) motors (also known as brushed DC motors) are widely used in motion control applications, such as in Electric Power Steering (EPS) systems, power tools, and the like. PMDC motors with multiple sets of windings have been developed to provide redundancy in EPS applications. Although these motors are similar to their typical single-winding counterparts, most common winding schemes result in inductive coupling between different sets of windings. This results in the current, and therefore torque, control behavior of these motors being different from that of single winding motors. Thus, existing control schemes cannot be extended to multi-phase PMDC motors

The torque control of the PMDC motor drive is performed by current regulation (by a current measurement circuit) with measured current feedback. For example, feed forward current and torque control is one mode of controlling a PMDC motor drive. Feedforward control is generally less prone to instability (due to the open-loop nature) and is noiseless because current sensors are generally not required to implement feedforward control. Furthermore, the noise transfer characteristics of the feedforward control system are lower compared to other control systems. Therefore, in applications such as EPS systems, power tools, etc., it is beneficial to operate a PMDC motor using feed forward current control.

Accordingly, it may be desirable to provide systems and methods for feed forward control of a PMDC motor drive, such as the systems and methods described herein. To achieve feed forward control of a PMDC motor drive, an accurate model of the PMDC motor (including non-linearities such as brush voltage drop) is required. For example, in some embodiments, the systems and methods described herein may be configured to: the control signal (e.g., voltage command) is determined or calculated by using an inverse mathematical model of the controlled object (or motor). In particular, the systems and methods described herein enable feed-forward current (torque) control of a multi-phase PMDC motor (e.g., having at least two sets of windings) based on a current command (reference) and a motor speed signal, which can be estimated or measured by a speed sensor or by differentiating a motor position obtained from a position sensor. In some embodiments, the machine model-based controller may be based on a substantially similar model of the PMDC machine with the estimated parameters. Additionally or alternatively, the speed parameter may be obtained directly from a sensor (position sensor or speed sensor) or observer output. In some embodiments, the transformed machine model-based controller may calculate the voltage command using an inverse of the modified machine model. The voltage command may be mathematically transformed for application to the PMDC machine terminal.

FIG. 1 generally illustrates a vehicle 10 according to the principles of the present disclosure. Vehicle 10 may include any suitable vehicle, such as a car, truck, sport utility vehicle, minivan, cross-over vehicle, any other passenger vehicle, any suitable commercial vehicle, or any other suitable vehicle. Although the vehicle 10 is illustrated as a passenger car having wheels and being used on a road, the principles of the present disclosure may be applied to other vehicles, such as airplanes, boats, trains, drones, or other suitable vehicles.

The vehicle 10 includes a vehicle body 12 and a hood 14. The passenger compartment 18 is at least partially defined by the vehicle body 12. Another portion of the vehicle body 12 defines an engine compartment 20. The hood 14 is movably attached to a portion of the vehicle body 12 such that the hood 14 provides access to the engine compartment 20 when the hood 14 is in a first or open position and the hood 14 covers the engine compartment 20 when the hood 14 is in a second or closed position. In some embodiments, the engine compartment 20 may be disposed in a rear portion of the vehicle 10 (as compared to what is generally shown).

The passenger compartment 18 may be disposed rearward of the engine compartment 20, but in embodiments where the engine compartment 20 is disposed in a rear portion of the vehicle 10, the passenger compartment 18 may be disposed forward of the engine compartment 20. The vehicle 10 may include any suitable propulsion system, including an internal combustion engine, one or more electric motors (e.g., an electric vehicle), one or more fuel cells, a hybrid (e.g., a hybrid vehicle) propulsion system including a combination of an internal combustion engine, one or more electric motors, and/or any other suitable configuration (e.g., a dual winding version).

In some embodiments, the vehicle 10 may include a gasoline-fueled engine, such as a spark-ignition engine. In some embodiments, the vehicle 10 may include a diesel fuel engine, such as a compression ignition engine. The engine compartment 20 houses and/or encloses at least some components of the propulsion system of the vehicle 10. Additionally or alternatively, propulsion control devices, such as an accelerator actuator (e.g., an accelerator pedal), a brake actuator (e.g., a brake pedal), a steering wheel, and other such components, are disposed in the passenger compartment 18 of the vehicle 10. The propulsion control devices may be actuated or controlled by a driver of the vehicle 10 and may be directly connected to corresponding components of the propulsion system, such as a throttle, a brake, an axle, a vehicle transmission (transmission), etc., accordingly. In some embodiments, the propulsion control device may communicate signals to a vehicle computer (e.g., drive-by-wire), which in turn may control corresponding propulsion components of the propulsion system. As such, in some embodiments, the vehicle 10 may be an autonomous vehicle.

In some embodiments, the vehicle 10 includes a transmission in communication with the crankshaft via a flywheel or clutch or fluid coupling. In some embodiments, the transmission comprises a manual transmission. In some embodiments, the transmission comprises an automatic transmission. In the case of an internal combustion engine or hybrid vehicle, the vehicle 10 may include one or more pistons that operate in conjunction with a crankshaft to generate a force that is transmitted through a transmission to one or more axles to turn the wheels 22. When the vehicle 10 includes one or more electric motors, the vehicle battery and/or fuel cell provides energy to the electric motors to rotate the wheels 22.

The vehicle 10 may include an automatic vehicle propulsion system, such as cruise control, adaptive cruise control, automatic brake control, other automatic vehicle propulsion systems, or a combination thereof. The vehicle 10 may be an automotive or semi-automotive vehicle, or other suitable type of vehicle. The vehicle 10 may include additional features or fewer features than those generally shown and/or disclosed herein.

In some embodiments, the vehicle 10 may include an ethernet component 24, a Controller Area Network (CAN) component 26, a media oriented system transfer component (MOST)28, a FlexRay component 30 (e.g., a brake-by-wire system, etc.), and a local interconnect network component (LIN) 32. In some embodiments, the vehicle 10 is configured for domain control with over-the-air programming support. For example, as described, the vehicle 10 may receive updates for any suitable software components of the vehicle 10 via the internet (e.g., or other suitable network). The vehicle 10 may update or change the software components based on the update. Vehicle 10 may include more or less features than those generally shown and/or disclosed herein.

In some embodiments, the vehicle 10 may include an Electric Power Steering (EPS) system that utilizes a PMDC motor. The PMDC motor may include a stator, a rotor, and a commutator (commutator). Typically, the stator contains poles and the rotor is an armature that carries windings. The commutator is attached to the brushes and slip rings, which allows mechanical commutation of the PMDC machine. The brushes are connected to phase lead terminals through which a voltage can be applied to the PMDC machine. The term "machine" is used interchangeably herein with the term "motor" and refers only to a PMDC motor (e.g., PMDC motor 520 shown in fig. 3-5) of a system (e.g., motor control system 300 shown in fig. 2-5).

The mathematical model of a single wound PMDC machine consists of two control equations that are related to the voltage, current and (electromagnetic) torque of the machine, as shown below.

e_g＝K_eω_m

T_e＝K_ei_a

Wherein v, i_aAnd T_eInput voltage, current and electromagnetic torque of the machine, K_eR and L represent the machine back EMF (and torque) constant, motor circuit resistance and inductance, respectively, e_gRepresents a back electromotive force voltage drop, andv_bthe non-linear brush voltage drop and is a function of current as follows.

Wherein, V₀And I₀Is the brush drop parameter. In general, all machine parameters are non-linear functions of operating temperature and magnetic saturation (caused by high current operation).

In addition, the electrical parameters of the motor (i.e., the back-emf constant or the torque constant K)_eResistance R and inductance L) dynamically changes with the operating conditions of the motor. For a given magnet temperature θ_m，K_eThe variation of (d) can be expressed as:

K_e＝γ_k(K_en(1+α_m(θ_m-θ_n)))

wherein, γ_kIs a scaling factor that takes into account magnetic saturation and is the motor current i_aFunction of, K_enIs at a temperature theta_nLower K_eA nominal (unsaturated) value of, and a_mIs a constant representing the thermal coefficient of the permanent magnet material used in the motor.

The inductance of the motor can be represented by the following equation:

L＝γ_lL_n

wherein, γ_LIs a scaling factor for the inductance based on the magnetic saturation characteristic of the motor and is the motor current i_aAnd L is a function of_nIs the nominal (unsaturated) inductance value.

Further, the motor circuit resistance may be described by the following equation:

R＝R_f(1+α_f(θ_f-θ_n))+R_m(1+α_w(θ_w-θ_n))

wherein R is_fIs the nominal value of the resistance of a Field Effect Transistor (FET), alpha_fIs a constant, θ, representing the thermal coefficient of the FET_fIs the temperature of the FET, θ_nIs to measure R_fNominal temperature of (A) time, R_mIs the nominal value of the motor resistance, alpha_wIs a constant, θ, representing the thermal coefficient of the winding_wIs the temperature of the winding, θ_nIs to measure R_mNominal temperature of (c).

The above equation for resistance provides the resistance of the motor circuit, not just the resistance of the motor windings. In some embodiments, the motor parameters are continuously estimated in real time or near real time, which may result in improved estimation of the signals used by the motor control system 300.

From a control system design perspective, PMDC motor 520 is the controlled object, and as described above, the time domain model of PMDC motor 520 can be transformed into the s-domain:

V(s)＝(LS+R)I_a(s(+E_g(s)+V_B(s)

the brushes of PMDC machines are typically susceptible to mechanical wear. Mechanical wear can cause the motor to fail, after which the machine will fail to operate. In an EPS system setting, not using a PMDC motor may result in the loss of assistance to the operator of the vehicle 10. To address this challenge, PMDC motors with multiple sets of windings have been developed to provide system redundancy.

Fig. 2 generally illustrates a motor control system 300 including a multi-winding PMDC machine according to the principles of the present disclosure. More specifically, the motor control system 300 is an example of a "double wound PMDC machine" that includes four stator poles (i.e., two pole pairs (N and S))110, two brush pairs (B1-B4)120, twelve commutator plates and rotor slots (i.e., gaps between rotor poles) 130 and commutator segments (e.g., 1.1-1.2, 1.3-1.4, 2.1-2.2, 2.3-2.4, 3.1-3.2, and 3.3-3.4)140 that correspond to each other, and a distributed lapped winding 150 having radial segments (diametripitch). It should be noted that the solution described herein is not limited to the motor control system 300 having the configuration shown in fig. 2. Rather, in other examples, the motor control system 300 may include additional brush pairs 120 and/or pole pairs 110. Alternatively or additionally, in other examples, motor control system 300 may include a different number of rotor slots 130 or a different manner of windings for commutator segments 140.

Although multi-winding PMDC motors are similar to their typical single-winding counterparts, most common winding schemes result in inductive coupling between different sets of windings. This results in the current, and thus torque, control behavior of these motors being different from that of single winding motors. Thus, existing control schemes for single winding PMDC motors cannot be extended to multi-phase PMDC motors. The torque control of the PMDC motor drive is performed by current regulation (by a current measurement circuit) with measured current feedback. For example, feed forward current and torque control is one mode of controlling a PMDC motor drive. To achieve feed forward control of the PMDC motor, an accurate model of the PMDC motor (including non-linearities such as brush voltage drop) is required.

Fig. 3 generally illustrates a block diagram of a dual winding PMDC machine using a mathematical model in accordance with the principles of the present disclosure. The view of motor control system 300 in fig. 3 includes a controller 510 and a PMDC motor 520, in which case motor 520 includes dual windings. Controller 510 may include any suitable controller, such as a vehicle electronic control unit, a processor, or any other suitable controller, such as those described herein. The controller 510 may be in communication with a memory. The memory may comprise any suitable non-volatile or volatile memory. The memory may include a memory array, a memory storage device, or any other suitable memory. The memory may include instructions that, when executed by the controller 510, cause the controller 510 to: at least the PMDC motor employed by the systems of the vehicle 10. Additionally or alternatively, the instructions, when executed by the controller 510, cause the controller 510 to perform various other functions of the vehicle 10.

For a dual winding PMDC motor 520, two input voltages (V)₁)530a and (V)₂)530b may be based on voltage commands generated by controller 510 (e.g., by a power controller (not shown)). It should be noted that although ideally the voltage command generated by controller 510 is equal to the input voltage (V) of PMDC motor 520₁)530a and (V)₂)530b, in practice, these values may be slightly different due to, for example, non-linearity of the power converter circuit. As described in more detail with reference to fig. 4 and 5As discussed, controller 510 may be based on one or more input torque command signals (e.g., the input current commands of fig. 4 and 5)And) A voltage command is determined. One or more input torque command signals may be based on input torqueAnd (4) generating.

In addition, due to the back electromotive force (ω) of each corresponding winding_m) The voltage command is modified. The back emf is based on the speed of motor 520. For example, a first back electromotive force voltage (ω) of a first set of windings of motor 520_m)532a is based on the motor speed and a first back emf (and torque) constant K for the first set of windings_e1. Similarly, a second back-emf voltage (ω) of the second set of windings of motor 520_m)532b based on motor speed and a second back emf (and torque) constant K for the second set of windings_e2。

Due to the brush voltage drop (V) of each winding_bd) And further modifies the voltage commands 530a-530 b. For example, a first voltage (V1)530a is added to the first winding's brush voltage drop, and a second voltage V₂Added to the brush voltage drop of the second winding. Converting the voltage to a current (I) for each winding based on the inductance and resistance of each winding₁)540a and (I)₂)540b, and the current further produces a resultant torque (T) from the motor 520_e)550. Based on a respective constant K for each winding_e1And K_e2Output torque 550 and current I₁And I₂And (4) in proportion. Furthermore, the magnetic coupling (represented by the mutual inductance (M)) between the two windings further affects the current generated by the voltage command.

The machine model of the machine 300 differs from that of a single winding machine due to the additional magnetic coupling between the phases of the dual winding PMDC machine 300. For example, a mathematical model for the dual wound PMDC machine 300 is given below.

T_e＝K_e1I₁+K_e2I₂

Wherein M is₁₂＝M₂₁And M denotes inductive coupling between two phases. Generally, the mutual inductance term (M)₁₂I₂And M₂₁I₁) Random machine current I₁And I₂A non-linear change.

The model can be extended to n-phase PMDC machines, where n represents the number of windings used (or the number of redundant machines included in a single PMDC machine). A general model of an n-phase machine can be represented as follows.

T_e＝K_e1I₁+K_e2I₂+…+K_enI_n

Where, in general, mutual inductance is specified to be different. The mutual inductance of two sets of windings (e.g., set a and set b) is the phaseEtc. (e.g. M)_ab＝M_ba)。

For simplicity, the remaining description is directed to a double winding machine, which can be extended to a general n-phase machine. The voltage-current equation of the double winding machine can be expressed in the form of a transfer matrix (transfer matrix) as follows.

Therein, it is assumed that the two brush-drop terms are independent of current in order to generate a transfer matrix representation of the PMDC machine (since a frequency domain representation of the transfer matrix requires a linear time-invariant model in the time domain). Therefore, the output current can be expressed as follows according to the input voltage.

Δ(s)＝(L₁s+R₁)(L₂s+R₂)-s²M²＝(L₁L₂-M²)s²+(L₁R₂+L₂R₁)s+R₁R₂

When the winding arrangement is symmetric and the two brush pairs are similar, the model described above can be simplified to assume that the half-machines are identical (e.g., self-inductance, resistance, voltage constant, and brush-drop parameters are equal).

Thus, in the dual winding PMDC machine 300, the controller 510 generates the output torque 550 using both windings simultaneously by generating voltage commands that cause the voltages 530a-530b to be generated such that the resulting current results in the output torque 550. Controller 510 generates voltage commands 530a-530b based on output torque 550 to be generated by motor 520. In the event of a failure of one winding (e.g., the first winding), the second voltage command 530b causes the second winding to continue to generate a corresponding current 540b, resulting in at least a partial output torque 550.

Alternatively or additionally, the controller 510 generates only a single voltage command to cause the input voltage (e.g., the first voltage 530a) to generate the output torque using only the first winding. In the event of a failure of the first winding, the controller 510 then uses the second winding to generate a second input voltage (V)₂)530b, thereby generating output torque 550.

The above model can be extended to n-winding PMDC machines (rather than just dual windings) where the controller 510 uses n (n is greater than 2) voltage commands V for n windings₁-V_nEach voltage command generating a corresponding current I₁-I_nAnd together they cause the motor to generate output torque 550.

It should be noted that the embodiments of feed forward control for multi-phase PMDC motors described herein may be applicable to any application where PMDC motors are used, such as boats, power tools, rotary pumps, and any other such application. PMDC motor drives are widely used in industry for low cost applications. Generally, feedback current control techniques are used for current and torque control of PMDC machines. The solution described herein facilitates the use of feed forward control and thus provides several advantages. For example, when a position sensor or a speed sensor is available, a current sensor is not required using feed forward control, thereby saving costs. In addition, the feed forward control reduces instability due to the open loop nature of the motor control system. In addition, the feed forward control provides fault tolerant control operation of the PMDC based drive system. Other advantages will be readily appreciated by those skilled in the art. The solution described herein provides different configurations of feed forward control of PMDC motors that can be used for different applications.

Feed forward current control uses motor speed for current control. Although the motor speed may be measured using a speed sensor or obtained by differentiating a position signal measured by a position sensor, an observer may also be used to estimate the motor speed.

Fig. 4 generally illustrates a block diagram of a system for feed forward current (and torque) control in accordance with the principles of the present disclosure. In fig. 4, motor control system 300 facilitates feed-forward control of PMDC motor 520, and thereby controls the torque output of PMDC motor 520. In some embodiments, the motor control system 300 includes a feed-forward current controller 510, among other components. The present disclosure uses the term "motor control system" to refer to the feed-forward current controller 510 and the PMDC motor 520. In some embodiments, the controller 510 controls the torque output 550 of the PMDC motor 520 by: the voltage is calculated using the inverse of the machine model of the PMDC motor 520 with the estimated parameters and commanded current. Any parametric representation with wave numbers shown in fig. 4 may estimate these parameters. These parameters can be estimated in real time by taking advantage of the temperature and magnetic saturation characteristics of the various portions of the PMDC motor 520.

As shown, voltage command 530a is based on the input current command402a, estimated brush voltage drop404a and estimated back EMF voltage drop406 a. Voltage command 530b is based on an input current command402b, estimated Brush Voltage drop404b and estimated back EMF voltage drop406 b.

The controller 510 generates the estimated brush voltage drops 404a and 404b using the following expression:

wherein the content of the first and second substances,andis a predetermined brush drop parameter, andandis a current command. While the brush drop estimate is shown as a function of the current command, it may also be estimated by replacing the current command with the measured motor current if a motor current measurement is available.

In addition, the controller 510 is based on the resistance of the motor circuitValue and inductanceEstimation of value, for input current command402a and402b generate 530a and 530 b. The resistance and inductance values of the motor circuit are predetermined or estimated values. Derivative termCan be in its standard form, e.g.The derivative terms may then be aligned using different techniques (e.g., backward differentiation, bilinear transformation, etc.)By discretizing, or derivative termsA direct digital derivative design with very targeted gain and phase response is possible to achieve the desired accuracy, complexity and noise transfer characteristics.

As depicted, controller 510 is based on a predetermined back EMF constant value and an estimated motor speedGenerating an estimated back EMF voltage drop406 a. The motor speed signal may be measured using a speed sensor or obtained by differentiating the motor position obtained from a position sensor. For example, the speed sensing circuit may monitor the motor speed and provide the detected speed as an input to the controller 510. The speed sensing circuit may have a transfer function that represents the dynamics of the speed sensor. In some embodiments, the low pass filter may use a predetermined cutoff frequency that depends on the motor speed.

In some embodiments, the feed forward control may utilize the velocity measured by the position sensor. The position sensing circuit may monitor the position of the motor and provide the detected position as an input to the controller 510. In some embodiments, the controller 510 includes a motor speed module that calculates an estimated motor speed based on the motor position signal. For example, the motor speed module may calculate the motor speed by differentiating the motor position signal. The motor position signal may provide an angular position of the motor shaft. For obtaining estimated motor speed from motor position signalsDerivative implementation of degreeMay have a structure such asCan then be implemented using different techniques (e.g., backward differentiation or bilinear transformation) for the derivativesPerforming discretization, or the derivative implementationA direct digital derivative design with very targeted gain and phase response is possible to achieve the desired accuracy, complexity and noise transfer characteristics. It should be noted that in other examples, the transfer function representing the dynamics of the position sensor may be different from the first order transfer function shown in the figures depending on the particular sensor characteristics.

In some embodiments, the brush drop parameter may be omitted from the motor control system 300 in an attempt to simplify from the controller 510. The motor control system 300 may be extended to any multi-phase machine having more than two sets of windings by extending the voltage term associated with mutual inductance to include cross-coupling between all sets of windings of the multi-phase machine.

FIG. 5 generally illustrates another exemplary block diagram of a motor control system 300 for feed-forward current (and torque) control in accordance with one or more embodiments. This control loop is implemented using an alternative mathematical model of the multi-winding machine shown generally in fig. 5, as follows.

V₊＝V₁+V₂ V_-＝V₁-V₂

I₊＝V₁+V₂ V_-＝V₁-V₂

T_e＝K_eI₊

As shown generally in fig. 5, the control logic is implemented based on current sum and difference commands as a function of the respective current commands. The control loop determines the voltage and command and the voltage difference command, which is then converted back to the respective voltage command and applied to the PMDC machine at 410. The current and control loop including resistance to the motor circuitValue, self-inductanceValue and mutual inductanceFeed forward estimation of values, and (modified) back EMFAnd brush voltage drop parameterWhile the current difference loop does not include the latter two terms. This alternative mathematical model allows to simplify the control logic implementation of the multiphase PMDC machine.

Fig. 6 is a flow chart generally illustrating a method 600 for controlling a multi-phase PMDC motor in accordance with the principles of the present disclosure. At 602, method 600 determines a first voltage command for a first set of windings of a multi-phase PMDC motor based on a first input torque command signal and a back emf voltage drop of the first set of windings. For example, the controller 510 determines a first voltage command for a first set of windings of the multi-phase PMDC motor based on the first input torque command signal and the back emf voltage drops of the first set of windings. At 604, method 600 determines a second voltage command based on the second input torque command signal for a second set of windings of the multi-phase PMDC motor. For example, the controller 510 determines a second voltage command based on the second input torque command signal for a second set of windings of the multi-phase PMDC motor. At 606, method 600 selectively controls the multi-phase PMDC motor according to the first voltage command and the second voltage command. For example, the controller 510 selectively controls the multi-phase PMDC motor according to the first voltage command and the second voltage command.

In some embodiments, a system for controlling output torque of a Permanent Magnet Direct Current (PMDC) machine includes: a PMDC motor configured to generate an output torque, the PMDC motor including a plurality of sets of windings; and a controller configured to: for a first set of windings of the PMDC motor, determining a first voltage command based on a first input torque command signal and a back emf voltage drop of the first set of windings; determining, for a second set of windings of the PMDC motor, a second voltage command based on the second input torque command signal; and selectively controlling the PMDC motor according to the first voltage command and the second voltage command.

In some embodiments, the controller is further configured to determine the first voltage command based on a brush voltage drop of the first set of windings.

In some embodiments, the controller is further configured to determine the second voltage command using the brush voltage drop and the back emf voltage drop of the second set of windings.

In some embodiments, the controller is further configured to determine the first voltage command based on an inductance of the circuitry of the PMDC motor and a resistance of the circuitry of the PMDC motor.

In some embodiments, the controller is further configured to determine the second voltage command based on an inductance of the circuitry of the PMDC motor and a resistance of the circuitry of the PMDC motor.

In some embodiments, the controller is further configured to: determining a voltage value based on the first input torque command signal, an inductance of the circuit of the PMDC motor, and a resistance of the circuit of the PMDC motor; and calculating the sum of the voltage value of the first set of windings and the back emf voltage drop.

In some embodiments, the controller is further configured to determine the first voltage command based on a sum of the voltage value and the voltage value, a brush voltage drop of the first set of windings, and a back emf voltage drop of the first set of windings.

In some embodiments, the controller is further configured to determine a back-emf voltage drop for the first set of windings using the motor speed signal estimate.

In some embodiments, the controller is further configured to: applying a first voltage command to a first set of windings, the first set of windings generating a first current in response to the first voltage command; and applying a second voltage command to a second set of windings, the second set of windings generating a second current in response to the second voltage command; wherein the PMDC motor generates an output torque in response to the first current and the second current.

In some embodiments, the controller is further configured to determine the first voltage command and the second voltage command using a mathematical transformation.

In some embodiments, a controller for controlling output torque of a multi-phase Permanent Magnet Direct Current (PMDC) motor is configured to: for a first set of windings of the multi-phase PMDC motor, determining a first voltage command based on the first input torque command signal and a back emf voltage drop across the first set of windings; determining, for a second set of windings of the multi-phase PMDC motor, a second voltage command based on the second input torque command signal; and selectively controlling the multi-phase PMDC motor according to the first voltage command and the second voltage command.

In some embodiments, the controller is further configured to determine the first voltage command based on a brush voltage drop of the first set of windings.

In some embodiments, the controller is further configured to determine the second voltage command using the brush voltage drop and the back emf voltage drop of the second set of windings.

In some embodiments, the controller is further configured to determine the first voltage command based on an inductance of the circuit of the multi-phase PMDC motor and a resistance of the circuit of the multi-phase PMDC motor.

In some embodiments, a method for controlling output torque of a multi-phase Permanent Magnet Direct Current (PMDC) motor includes: for a first set of windings of the multi-phase PMDC motor, determining a first voltage command based on the first input torque command signal and a back emf voltage drop across the first set of windings; determining, for a second set of windings of the multi-phase PMDC motor, a second voltage command based on the second input torque command signal; and selectively controlling the multi-phase PMDC motor according to the first voltage command and the second voltage command.

In some embodiments, the method further includes determining a first voltage command based on the brush voltage drop of the first set of windings.

In some embodiments, the method further includes determining a second voltage command using the brush voltage drop and the back emf voltage drop of the second set of windings.

In some embodiments, the method further includes determining the first voltage command based on an inductance of the circuit of the multi-phase PMDC motor and a resistance of the circuit of the multi-phase PMDC motor.

In some embodiments, the method further comprises determining a back-emf voltage drop for the first set of windings using the motor speed signal estimate.

In some embodiments, the method further comprises: applying a first voltage command to a first set of windings, the first set of windings generating a first current in response to the first voltage command; and applying a second voltage command to a second set of windings, the second set of windings generating a second current in response to the second voltage command; wherein the multi-phase PMDC motor generates an output torque in response to the first current and the second current.

The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.

The word "example" is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the word "example" is intended to present concepts in a concrete fashion. As used in this application, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless specified otherwise, or clear from context, "X comprises a or B" is intended to mean any of the natural inclusive permutations. That is, if X contains A; x comprises B; or X includes both A and B, then "X includes A or B" is satisfied under any of the foregoing circumstances. In addition, the articles "a" and "an" as used in this application and the appended claims should generally be construed to mean "one or more" unless specified otherwise or clear from context to be directed to a singular form. Furthermore, unless described as such, the use of the term "embodiment" or "one embodiment" throughout is not intended to refer to the same embodiment or implementation.

Implementations of the systems, algorithms, methods, commands, etc. described herein may be implemented in hardware, software, or any combination thereof. The hardware may include, for example, a computer, an Intellectual Property (IP) core, an Application Specific Integrated Circuit (ASIC), a programmable logic array, an optical processor, a programmable logic controller, microcode, a microcontroller, a server, a microprocessor, a digital signal processor, or any other suitable circuitry. In the claims, the term "processor" should be understood to include any of the foregoing hardware, alone or in combination. The terms "signal" and "data" are used interchangeably.

As used herein, the term module may include a packaged functional hardware unit designed for use with other components, a set of commands executable by a controller (e.g., a processor executing software or firmware), processing circuitry configured to perform specific functions, and self-contained hardware or software components interfaced with a large system. For example, a module may include, or be a combination of, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a circuit, digital logic, analog circuitry, a combination of discrete circuits, gates, and other types of hardware. In other embodiments, a module may include a memory that stores commands executable by a controller to implement features of the module.

Further, in an aspect, for example, the systems described herein may be implemented using a general purpose computer or a general purpose processor with a computer program that, when executed, performs any of the corresponding methods, algorithms, and/or commands described herein. Additionally or alternatively, for example, a special purpose computer/processor may be utilized which may contain other hardware for carrying out any of the methods, algorithms, or commands described herein.

Furthermore, all or a portion of an implementation of the present disclosure may take the form of a computer program product accessible from, for example, a computer-usable or computer-readable medium. A computer-usable or computer-readable medium may be, for example, any apparatus that can tangibly contain, store, communicate, or transport the program for use by or in connection with any processor. The medium may be, for example, an electrical, magnetic, optical, electromagnetic or semiconductor device. Other suitable media may also be used.

The above-described embodiments, embodiments and aspects have been described to allow easy understanding of the present invention and do not limit the present disclosure. On the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.