Active loss generation using disengaged motor

Abstract

A power module includes an inverter switch configured to control a supply of current to a plurality of stator coils of a motor. A control module of the power module is configured to invoke supply of an amount of current to the motor by the inverter switch according to the current command while maintaining a rotor of the motor substantially stationary. For example, a control module may be configured to generate ripple torque commands that alternate between positive and negative by a predefined period. The control module also generates a feedback torque command based on the feedback speed of the rotor to drive the speed of the rotor toward zero. The feedback torque command may be combined with the ripple torque command to obtain a total torque command.

Description

[0001] Related patent applications

[0002] This application claims priority to U.S. Provisional Application Serial No. 63 / 688,802, filed August 29, 2024, entitled “ACTIVE LOSS GENERATION USING DISENGAGED MOTOR”. Background Technology

[0003] This disclosure relates to the generation of active losses using a disengaged motor. Summary of the Invention

[0004] This disclosure describes a method for inducing losses in a disengaged motor. In one aspect, an inverter switch is configured to control the current supply to a plurality of stator coils of the motor. A control module is configured to cause the inverter switch to supply a certain amount of current to the motor according to a current command, while keeping the motor rotor substantially stationary. For example, the control module may be configured to generate a ripple torque command that alternates between positive and negative at a predefined period. Attached Figure Description

[0005] Figure 1A Example vehicles that can be operated according to certain implementation schemes are illustrated.

[0006] Figure 1B An example is shown of a chassis of a vehicle with multiple drive units that is operable according to certain embodiments.

[0007] Figure 2 It is a schematic block diagram of components used to operate a vehicle according to certain implementation schemes.

[0008] Figure 3 This is a schematic block diagram illustrating the power module of a vehicle according to certain implementation schemes.

[0009] Figure 4 This is a schematic diagram of the components of a drive unit according to certain implementation schemes.

[0010] Figure 5 This is a schematic diagram illustrating the distribution of regenerative current according to certain implementation schemes.

[0011] Figure 6 It is a schematic block diagram of a component used to control the current supplied to the disconnect motor in order to realize the active loss generation according to certain implementation schemes. Detailed Implementation

[0012] A vehicle includes multiple motors, one of which can be disconnected when not needed. The disconnected motor can still be used to generate active losses, such as receiving regenerative current when the battery cannot receive it, and to generate heat for regulating the battery. A power module for controlling the current supply to the disconnected motor generates a ripple torque command that alternates between positive and negative values ​​at a predefined period. A total torque command can be obtained by adding the ripple torque command to a feedback torque command based on the motor's sensed speed, where the feedback torque command is selected to drive the motor speed toward zero. The total torque command and the current command are used to control the inverter switching that supplies current to the motor. The current command is the amount of current commanded to be drawn by the disconnected motor to absorb regenerative current and / or generate heat.

[0013] Figure 1A An example vehicle 100 in which the methods described herein can be implemented is illustrated. Figure 1A As shown, vehicle 100 has multiple external cameras 102 and one or more front displays 104. Each of these external cameras 102 can capture a specific view or perspective of the exterior of vehicle 100. The images or videos captured by the external cameras 102 can then be displayed on one or more displays in vehicle 100, such as one or more front displays 104, for the driver to view.

[0014] refer to Figure 1B The vehicle 100 may include a chassis 106, which includes a frame 108 that provides the main structural components of the vehicle 100. The frame 108 may be formed by one or more beams or other structural components, or may be integral with the vehicle body (e.g., a monolithic construction).

[0015] In embodiments where vehicle 100 is a battery electric vehicle (BEV) or possibly a hybrid vehicle, a large battery 110 is mounted to the chassis 106 and may occupy a significant portion (e.g., at least 80%) of the area within the frame 108. For example, battery 110 may store 100 to 200 kWh. Battery 110 may be a lithium-ion battery or other types of rechargeable battery. The battery may be substantially planar in shape.

[0016] Power from battery 110 can be supplied to one or more drive units 112. Each drive unit 112 may be formed by an electric motor and, possibly, a gear train providing gear reduction. In some embodiments, a single drive unit 112 is present, which drives the front or rear wheels of vehicle 100. In another embodiment, two drive units 112 are present, each driving the front or rear wheels of vehicle 100. In yet another embodiment, four drive units 112 are present, each driving one of the four wheels of vehicle 100.

[0017] Power from the battery 110 can be supplied to the drive unit 112 via one or more power modules 114 (such as power modules for each drive unit 112 or a pair of drive units 112). The power modules 114 may include inverters configured to convert direct current (DC) from the battery 110 into alternating current (AC) supplied to the motor of the drive unit 112. The power modules 114 also facilitate the operation of the drive unit's motor as a generator to provide regenerative braking. The power modules 114 further facilitate the transfer of regenerative current to the battery 110.

[0018] A drive unit 112 is coupled to two or more wheel hubs 116 to which wheels can be mounted. Each wheel hub 116 includes a corresponding brake 118, such as a disc brake as illustrated. Each wheel hub 116 is further coupled to a frame 108 via a suspension 120. The suspension 120 may include metal or pneumatic springs for absorbing shocks. The suspension 120 may be implemented as a pneumatic or hydraulic suspension capable of adjusting the ground clearance of the chassis 106 relative to a supporting surface. The suspension 120 may include a damper, wherein the characteristics of the damper are fixed or electronically adjustable.

[0019] exist Figure 1B In the implementation scheme and in the discussion below, vehicle 100 is a battery electric vehicle. However, hybrid electric vehicles can also benefit from the methods described herein. Similarly, non-vehicle applications using inverters or other related power components can also benefit from the methods described herein.

[0020] Figure 2 Examples Figure 1A Example components of vehicle 100. (e.g.) Figure 2 As shown, vehicle 100 includes a camera 102, one or more front displays 104, a user interface 200, one or more sensors 202, a motion sensor 204, and a positioning system 206. The one or more sensors 202 may include ultrasonic sensors, radio detection and ranging (RADAR) sensors, light detection and ranging (LIDAR) sensors, or other types of sensors. The positioning system 206 may be implemented as a Global Positioning System (GPS) receiver. The user interface 200 allows a user (such as a driver or occupant in vehicle 100) to provide input.

[0021] Components of vehicle 100 may include one or more temperature sensors 208. Temperature sensors 208 may include sensors configured to sense ambient air temperature, battery 110 temperature, power module 114 temperature, temperature of each drive unit 112 and / or each motor of each drive unit 112 temperature, temperature of coolant fluid entering or leaving the coolant system, oil temperature within drive unit 112, or the temperature of any other component of vehicle 100. Temperature sensors 208 may include temperature sensors directly mounted to the microprocessor of power module 114, as described in more detail below.

[0022] The control system 214 executes instructions to perform at least some of the actions or functions of the vehicle 100. For example, such as... Figure 2 As shown, the control system 214 may include one or more electronic control units (ECUs) configured to perform at least some of the actions or functions of the vehicle 100, including regarding... Figures 3 to 6 The functions described. In some implementations, each ECU in the ECU is dedicated to a specific set of functions.

[0023] Some features of the implementation scheme described herein can be controlled by a telematics control module (TCM) ECU. The TCM ECU can provide a wireless vehicle communication gateway to support functionality, by way of example and not limitation, such as over-the-air (OTA) software updates, vehicle-to-Internet communication, vehicle-to-computing device communication, in-vehicle navigation, vehicle-to-vehicle communication, vehicle-to-landscape features (e.g., automatic toll road sensors, automatic toll booths, power distributors at charging stations), or automatic calling functionality.

[0024] Some features of the implementation described herein can be controlled by a Central Gateway Module (CGM) ECU. The CGM ECU serves as the vehicle's communication hub, connecting various ECUs, sensors, cameras, microphones, motors, displays, and other vehicle components, and transmitting data to and from these components. The CGM ECU may include a network switch providing connectivity via a Controller Area Network (CAN) port, a Local Interconnect Network (LIN) port, and an Ethernet port. The CGM ECU can also function as the master controller for different vehicle modes (e.g., road driving mode, parking mode, off-road mode, trailer mode, camping mode), thereby controlling certain vehicle components associated with placing the vehicle in one of these vehicle modes.

[0025] In various implementations, the CGM ECU collects sensor signals from one or more sensors of the vehicle 100. For example, the CGM ECU may collect data from camera 102, sensor 202, motion sensor 204, positioning system 206, and temperature sensor 208. The sensor signals collected by the CGM ECU are then transmitted to the appropriate ECU for processing.

[0026] The control system 214 may also include one or more additional ECUs, as an example and not a limitation, such as a vehicle dynamics module (VDM) ECU, an experience management module (XMM) ECU, a vehicle access system (VAS) ECU, a near field communication (NFC) ECU, a body control module (BCM) ECU, a seat control module (SCM) ECU, a door control module (DCM) ECU, a rear zone control (RZC) ECU, an autonomous control module (ACM) ECU, an autonomous safety module (ASM) ECU, a driver monitoring system (DMS) ECU, and / or a winch control module (WCM) ECU.

[0027] If vehicle 100 is an electric vehicle, one or more ECUs may provide functionality related to the vehicle's battery pack, such as a Battery Management System (BMS) ECU, a Battery Power Isolation (BPI) ECU, a Balanced Voltage and Temperature (BVT) ECU, and / or a Thermal Management Module (TMM) ECU. In various implementations, the XMM ECU sends data to the TCM ECU (e.g., via Ethernet, etc.). Additionally or alternatively, the XMM ECU may send other data (e.g., audio data from microphone 216, etc.) to the TCM ECU.

[0028] refer to Figure 3 The power module 114 may be included within a housing 300, such as a housing made of aluminum or steel. The power module 114 may include multiple components configured to convert direct current (DC) from the battery 110 into alternating current (AC), such as three-phase AC, which is supplied to one or more motors 302 of the drive unit 112 including the power module 114.

[0029] The power module 114 can receive power from the battery 110 via a DC link capacitor 304 connected to the positive and negative terminals (Batt+, Batt-) of the battery 110, and use it to smooth the current received from the battery 110 as part of the process of converting the direct current from the battery 110 into an approximately sinusoidal alternating current. The DC link capacitor 304 can further be used to suppress any voltage spikes. The DC link capacitor 304 can be inside or outside the housing 300.

[0030] Power module 114 may include an inverter switch 306 coupled to the output of DC link capacitor 304. Inverter switch 306 may include multiple switches that are selectively opened and closed to allow current to be delivered at an appropriate frequency to the output of power module 114 for driving one or more motors 302. For example, inverter switch 306 may output three-phase current via line 308 connecting inverter switch 306 to motor 302. The opening and closing of the switches in inverter switch 306 may be controlled by control module 310. Control module 310 may include a printed circuit board having various electronic components configured to generate control signals for inverter switch 306. In some embodiments, power module 114 drives two drive units 112 and includes separate printed circuit boards for supplying current to the motors 302 of each individual drive unit.

[0031] The control module 310 may also include a microprocessor 312 programmed to control the operation of the control module 310 and thus control the inverter switch 306. The microprocessor 312 may be specifically embodied as a silicon chip mounted on a printed circuit board of the control module 310. The microprocessor 312 may include a temperature sensor 314 directly mounted thereon.

[0032] The control module 310 can be coupled to the control system 214 and implement instructions from the control system 214 to control the current supplied to the motor 302 and cause the motor 302 to generate regenerative current. The control system 214 can generate such instructions as part of an autonomous driving algorithm (e.g., adaptive cruise control), a safety algorithm (e.g., traction control, stability control, automatic emergency braking), or in response to inputs from the driver via the accelerator pedal 316 and / or the brake pedal 318.

[0033] Motor 302 may include rotor 322a and stator coil 322b. Stator coil 322b includes a conductor loop through which current flows to induce a stator magnetic field acting on rotor 322a. Rotor 322a includes: (a) a permanent magnet acting on the stator magnetic field to induce torque on shaft 322c of motor 302, or (b) a conductive rod in which current is induced by the stator magnetic field to generate a corresponding rotor magnetic field that interacts with the stator magnetic field to induce torque on shaft 322c.

[0034] When rotor 322a includes a permanent magnet, the rotation of rotor 322a when motor 302 is not in use induces a current in stator coil 322b and a corresponding magnetic field that resists the rotation of rotor 322a. Therefore, it is advantageous to disconnect shaft 322c from the wheels of vehicle 100 when motor 302 is not in use.

[0035] For example, refer to Figure 4The drive unit 112 may include a disconnector 400 inserted between the motor 302 and the drive gear 402. The drive gear 402 transmits torque to an axle 404 connected to one or more wheels of the vehicle 100. The vehicle dynamics module (VDM) 406 of the control system 214 is configured to control the current supply to the motor 302 and to control the state of the disconnector 400, i.e., to connect the motor 302 to the drive gear 402 or to disconnect the motor 302 from the drive gear 402. The disconnector 400 may also be inserted between the drive gear 402 and the axle 404 or between the axle 404 and one or more wheels of the vehicle 100.

[0036] refer to Figure 5 The vehicle 100 can operate in the illustrated configuration, in which one motor 302a is engaged, for example, connected to one or more first wheels of the vehicle 100, and another motor 302b is disengaged, for example, not connected to one or more second wheels of the vehicle 100. This configuration may be useful when torque from the two motors 302a, 302b is not required to achieve a target speed for the vehicle 100, or when the vehicle 100 is operating in an energy-saving mode.

[0037] The drive unit 112, including motor 302a, can be configured such that motor 302a is always engaged. In one example, motor 302a engages with the first two wheels of vehicle 100, and motor 302b selectively engages with the last two wheels of vehicle 100. In some embodiments, engaging motor 302a may be an induction motor, while disengaging motor 302b may be a permanent magnet motor.

[0038] Motors 302a and 302b may be connected to battery 110 to deliver regenerative current to or receive current from battery 110. In the illustrated embodiment, motors 302a and 302b are connected to battery 110 via capacitor 500 (such as a high-voltage direct current (HVDC) capacitor). The HVDC capacitor 500 may be a single capacitor to which both motors 302a and 302b are connected, or a separate HVDC capacitor 500 for each motor 302a and 302b (e.g., a DC link capacitor 304 for each drive unit 112).

[0039] During normal operation, the engagement motor 302a can periodically generate regenerative current, such as during regenerative braking. In some scenarios, the battery 110 may not be able to receive the full amount of regenerative current. This may occur when the battery 110 is at or near its state of full charge (SOC) or when the battery temperature is too low or too high to receive current without damaging the battery 110. It may be desirable to maintain the amount of regenerative current above the capacity of the battery 110 in order to provide a consistent amount of stopping force (e.g., a consistent amount of stopping force for a given amount of force applied to the brake pedal 318) independent of the condition of the battery 110.

[0040] In such a scenario, disengaging motor 302b allows it to operate in a lossy manner to convert electrical current into heat. This heat can be dissipated by a coolant circulated by cooling system 502. The coolant can be circulated to allow thermal contact with motors 302a, 302b, and battery 110. Cooling system 502 may include a radiator for exchanging heat with ambient air and may include a cooler as part of a vapor compression refrigeration system.

[0041] In another scenario, the battery 110 is below the desired temperature, whether for supplying current to the engaging motor 302a or for receiving current when charging the battery. In this scenario, disengaging the motor 302b can also be performed in a lossy manner to convert the current into heat conducted to the battery 110 by the cooling system 502.

[0042] Using the method described herein, motor 302b is disengaged in a destructive manner while keeping rotor 322a substantially stationary, for example, within a position range of 1 degree, 0.1 degree, or 0.01 degree. Disengaging motor 302b in this manner facilitates re-engagement of motor 302b by VDM 406 using disconnect device 400 when necessary. For example, VDM 406 may assume that when motor 302b is re-engaged, rotor 322a does not rotate (e.g., at a speed less than 10 revolutions per minute (RPM), 5 RPM, or 1 RPM) and / or is within tolerances of a known position (e.g., 5 degrees, 1 degree, or 0.1 degrees).

[0043] Figure 6An example control architecture 600 is illustrated for lossy operation of the disconnected motor 302b in any of the scenarios described above. The illustrated control architecture 600 can be implemented by a power module 114, such as by a control module 310 of the power module 114, which is part of a drive unit 112 that includes the disconnected motor 302b, wherein the inverter switch 306 is also used as outlined below. The control architecture 600 can implement commands received from the control system 214, such as commands to consume a certain amount of current while keeping the motor 302b of the drive unit 112 substantially stationary, as defined above.

[0044] The control architecture 600 can generally be described as commanding the alternating torque (“ripple torque”) and zero speed of the motor 302b, while also commanding current draw corresponding to the amount of current required for one or both of the following: (a) consuming excess regenerative current that cannot be received by the battery 110, and (b) generating heat for regulating the battery 110.

[0045] For example, the ripple torque command 602 can command positive and negative torques to alternate at a predefined period. The ripple torque command 602 can be generated by the control module 310 itself. The durations of the positive and negative torque periods can be substantially equal (within tolerances achievable by the components used, e.g., within 2% of the equivalent value), and together constitute 100% of the duration of the ripple torque command 602; for example, 50% duty cycles of the positive torque are alternated with 50% duty cycles of the negative torque. The magnitudes of the positive and negative torque periods can be substantially equal (e.g., within tolerances achievable by the components used, e.g., within 2% of the equivalent value).

[0046] The magnitude and duration of the positive and negative torque cycles can be based on the frequency response of motor 302. For example, the magnitude and duration can be selected such that when the torque of motor 302 is controlled solely according to ripple torque command 602, motor 302 will experience oscillations with magnitudes less than 1 degree, 0.5 degrees, 0.1 degrees, or 0.01 degrees. In one example, the magnitude is selected to be between 20 Nm and 1 Nm, between 10 Nm and 1 Nm, or between 5 Nm and 1 Nm. The duration of each positive and negative cycle can be selected to be less than 100 milliseconds, 10 milliseconds, or 1 millisecond. In some embodiments, the duration is selected based on the switching speed of the components used (e.g., the switching speed of inverter switch 306 or a multiple thereof (e.g., a multiple less than 4, 2, or smaller)). The duration can be selected based on the maximum rotational speed of motor 302b (e.g., a limit imposed by the components controlling the speed of motor 302b). For example, the duration can be 1 / (M*R), where R is the maximum rotational speed in revolutions per second, and M is a multiple, such as a value greater than 1, greater than 2, greater than 10, or greater than 100. In some implementations, for example, the duration of the predefined period of the ripple current can be less than 1 / M, where M is the maximum rotational speed of the motor in revolutions per second.

[0047] In some implementations, speed feedback is used in conjunction with a ripple torque command 602 to account for inaccuracies in the generation and / or implementation of the torque command and to prevent the motor 302 from starting to rotate. For example, a motor speed feedback signal 606 and a zero-speed command 608 may be input to a feedback controller 604, such as a proportional-integral-derivative (PID) controller. The feedback controller 604 selects a feedback torque command based on a transfer function that will drive the motor speed feedback signal 606 toward zero over time. When the disengaged motor 302b is engaged, the zero-speed command 608 may be replaced by a speed command from the control system 214, corresponding to an input from a user (e.g., the position of the accelerator pedal 316) or an automated system (e.g., cruise control or other automatic driving system).

[0048] The feedback torque command output from the feedback controller 604 can then be combined with the ripple torque command 602, such as by summing the ripple torque command 602 and the feedback torque command at the summing stage 610 to obtain the total torque command. Using the ripple torque command 602 along with speed feedback helps prevent the rotor 302c from rotating during any delays in implementing speed feedback, such as transmission delays or the finite frequency response of the feedback controller 604.

[0049] The desired amount of loss can be determined based on the DC current command 612 and the HVDC voltage 614. The DC current command 612 is the amount of regenerative current currently generated that exceeds the capacity of the current received by the battery 110, or a function of that amount. Additionally or alternatively, the DC current command 612 may be a function of the amount of heating required by the battery 110, for example, a value obtained based on the sensed temperature of the battery 110 (such as a temperature feedback controller). The HVDC voltage 614 may be a sensed value of the voltage at the output terminal (e.g., Batt+) of the battery 110 or at the input terminal of the disconnected motor 302b.

[0050] The DC current command 612 and the HVDC voltage 614 can be multiplied together, for example, by a multiplier stage 616, to obtain a power command, such as the amount of power that the motor 302b should consume when disengaged.

[0051] A power command can be input to a motor controller 618, which outputs a corresponding input current command. For example, the motor controller 618 can be a controller that converts the commanded power amount (e.g., based on the position of the accelerator pedal 316) into a current demand. The motor controller 618 can be implemented using lookup tables or other types of control algorithms. In other embodiments, the DC current command 612 is used as an input current command in a bypass of the motor controller 618. Using the motor controller 618 has the advantage of using existing programmable components of the control module 310. However, in other embodiments, another component can implement the functions attributed herein to the motor controller 618 related to generating losses while keeping the motor 302 substantially stationary, as defined above. For example, the motor controller 618 can be replaced by the control module 310, the power module 114, or a separate control module within the control system 214.

[0052] The total torque command and the input current command can be input to the vector current stage 620. The vector current stage 620 determines the timing and amount of current applied to each coil in the stator coils 322b based on the total torque command and the input current command. Therefore, the output of the vector current stage 620 can be a signal for each stator coil 322b, each signal indicating a time-varying current target for that stator coil 322b. The vector current stage 620 can be implemented as any vector current controller known in the art (e.g., a direct quadrature (DQ) controller).

[0053] The output signal of the vector current stage 620 can be input to a current controller 622, which controls the switch supplying current to the stator coil 322b to achieve the current target specified in the output signal within the limits of the current controller 622. The current controller 622 can be implemented as the inverter switch 306 or other components of the power module 114.

[0054] Feedback control based on the motor speed feedback signal 606 and the ripple torque command 602 ensures that the rotor 302c remains substantially stationary. Control by the motor controller 618 based on the DC current command 612 ensures that the current drawn by the motor 302 (e.g., the root mean square (RMS) current) is substantially equal to the DC current command 612 (e.g., within 10%, 5%, or 1% of the DC current command).

[0055] Clearly, the control architecture 600 enables the disconnected motor 302b to draw a specified amount of current while also performing feedback control to prevent the rotor 302c from rotating. The control architecture 600 can achieve this using only one input (DC current command 612) from the VDM 406 of the control system 214. The control architecture 600 itself can be implemented within the control module 310, or by some other component within the power module 114, which is separate from the control system 214. For example, the control module 310 can implement the control architecture 600 in response to receiving the DC current command 612 when the motor 302b is disconnected.

[0056] Using the method described above, disconnecting the motor 302b can, for example, enable the generation of an additional 10 Nm of regenerative braking or 10 kW of heat for battery regulation. The method described above may be limited by the temperature constraints of the disconnecting motor 302b. For example, if a temperature sensor indicates that the disconnecting motor 302b is above a threshold temperature, the control module 310 may notify the VDM, which may then reduce the DC current command 612 in response to the notification. The VDM may also take other actions in response to the notification, such as reducing regenerative braking, increasing friction braking, or drawing heat from another source to regulate the battery (e.g., a resistance heater).

[0057] Various embodiments of this disclosure have been described for illustrative purposes. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein has been chosen to explain the principles of the embodiments, their practical application, or technical improvements to technologies found in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0058] In the foregoing, reference has been made to the embodiments presented in this disclosure. However, the scope of this disclosure extends beyond the specifically described embodiments. Rather, any combination of features and elements is contemplated for implementing and practicing the contemplated embodiments, whether or not different embodiments are involved. Furthermore, while the embodiments disclosed herein may achieve advantages over other possible solutions or over the prior art, the embodiments may achieve some advantages or no particular advantages. Therefore, the aspects, features, embodiments, and advantages discussed herein are merely illustrative.

[0059] While the foregoing relates to embodiments of this disclosure, other and further embodiments may be devised without departing from the basic scope of this disclosure, the scope of which is defined by the appended claims.

Claims

1. A power module comprising: an inverter switch configured to control a supply of current to a plurality of stator coils of a motor; and a control module configured to cause the inverter switch to supply an amount of current to the motor in accordance with a current command and a torque command to keep a rotor of the motor substantially stationary, the torque command comprising a ripple torque command that alternates between positive and negative at a predefined period.

2. The power module of claim 1, wherein the predefined period is less than 10 milliseconds.

3. The power module of claim 1, wherein the torque command comprises a feedback torque command, and the control module is further configured to: receive a speed feedback signal indicative of a speed of the motor; generate the feedback torque command to drive the speed of the motor towards zero; combine the ripple torque command and the feedback torque command to obtain the torque command; and control the inverter switch based on the torque command.

4. The power module of claim 3, wherein the control module is further configured to generate the feedback torque command from the speed feedback signal using a proportional-integral-derivative feedback controller.

5. The power module of claim 3, wherein the control module is further configured to control the inverter switch in accordance with the current command and the torque command such that an amount of current drawn by the motor is substantially equal to the current command while keeping the rotor of the motor substantially stationary.

6. The power module of claim 3, wherein the control module is further configured to control the inverter switch in accordance with the current command and the torque command such that the amount of current is within 10% of the current command while keeping movement of the rotor of the motor within a 1 degree range of position.

7. The power module of claim 3, wherein the control module is further configured to: determine an input current from the current command and a voltage of a battery coupled to the power module; and generate a vector current from the torque command and the input current, the vector current defining a timing and amount of current to be applied to each of the plurality of stator coils using the inverter switch.

8. A vehicle comprising: a plurality of wheels; a motor; a disconnect device configured to selectively engage the motor with one or more first wheels of the plurality of wheels; a power module configured to control the motor; and a control system configured to: instruct the disconnect device to disengage the motor from the one or more first wheels; and output a current command to the power module while the motor is disengaged from the one or more first wheels; wherein the power module is configured to supply an amount of current to the motor in accordance with the current command while keeping a rotor of the motor substantially stationary.

9. The vehicle of claim 8, wherein: ​ ​ The motor is a first motor, the vehicle further comprising a second motor coupled to one or more second wheels of the plurality of wheels; and The control system is configured to determine the current command as a function of an amount of regenerative current generated by the second motor.

10. The vehicle of claim 9, the vehicle further comprising a battery; wherein the control system is configured to determine the current command as a function of the amount of regenerative current generated by the second motor and a current receiving capacity of the battery.

11. The vehicle of claim 10, wherein the control system is configured to determine the current receiving capacity of the battery as a function of a state of charge and a temperature of the battery.

12. The vehicle of claim 8, the vehicle further comprising a battery and a cooling system coupled to the battery and the motor; wherein the control system is configured to determine the current command as a function of a temperature of the battery.

13. The vehicle of claim 12, wherein the cooling system is configured to circulate a coolant in thermal contact with the battery and the motor.

14. The vehicle of claim 8, wherein the power module further comprises inverter switches, the power module further configured to generate a ripple torque command that alternates between positive and negative at a predefined period.

15. The vehicle of claim 14, wherein the predefined period is less than 10 milliseconds.

16. The vehicle of claim 14, wherein the power module is further configured to: receive a speed feedback signal indicative of a speed of the motor; generate a feedback torque command determined to drive the speed of the motor towards zero; combine the ripple torque command and the feedback torque command to obtain a total torque command; and control the inverter switches based on the total torque command.

17. The vehicle of claim 16, wherein the power module is configured to generate the feedback torque command from the speed feedback signal using a proportional-integral-derivative feedback controller.

18. The vehicle of claim 16, wherein the power module is further configured to control the inverter switches as a function of the current command and the total torque command such that an amount of current is substantially equal to the current command while keeping the rotor of the motor substantially stationary.

19. The vehicle of claim 16, wherein the power module is further configured to control the inverter switches as a function of the current command and the total torque command such that the amount of current is within 10% of the current command while keeping movement of a rotor of the motor within a 1 degree range of position.

20. The vehicle of claim 16, wherein the power module is further configured to: determine an input current as a function of the current command and a voltage of a battery coupled to the power module; and generate a vector current as a function of the total torque command and the input current, the vector current defining a timing and amount of current to be applied to each stator coil of the motor using the inverter switches.

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