Optimal torque control of a multiphase synchronous motor with open circuit conditions

Abstract

The present application discloses optimal torque control of a multiphase synchronous motor with an open circuit condition. A method for controlling a multiphase motor includes: in response to determining that a phase of the multiphase motor is in an open circuit condition, determining a desired torque to be generated by the multiphase motor; and retrieving a set of current values ​​to be applied to each of the other phases of the multiphase motor to achieve the desired torque based on the determination that the phase is in the open circuit condition and the desired torque. The method may also include: applying individual current values ​​of the set of current values ​​to corresponding phases of the other phases of the multiphase motor, the set of current values ​​being determined based on a model of the multiphase motor including the phase in the open circuit condition.

Description

Technical Field

[0001] The present disclosure relates to electric machines, and in particular to controlling a multi-phase electric machine having one phase in an open circuit condition. Background Art

[0002] Vehicles such as automobiles, trucks, sport utility vehicles, crossovers, minivans, boats, aircraft, all-terrain vehicles, recreational vehicles, or other suitable vehicles often include one or more electric machines, such as electric motors, etc. For example, a vehicle may include one or more multi-phase electric machines configured to control various aspects of a steering system of the vehicle.

[0003] Multiphase electric machines (e.g., multiphase permanent magnet synchronous motor drives) can provide significant advantages over conventional machines, including improved efficiency, improved fault tolerance, and relatively low torque ripple (e.g., especially under fault conditions). As a result, such multiphase electric machines are increasingly used in safety-critical industrial applications, especially in the automotive and aerospace industries. Summary of the invention

[0004] The present disclosure generally relates to multi-phase electric machines.

[0005] One aspect of the disclosed embodiment includes a method for controlling a multi-phase electric machine. The method includes: in response to determining that a phase of the multi-phase electric machine is in an open circuit condition, determining a desired torque to be produced by the multi-phase electric machine; and retrieving a set of current values ​​to be applied to each of the other phases of the multi-phase electric machine to achieve the desired torque based on the determination that the phase is in the open circuit condition and the desired torque. The method may also include: applying individual current values ​​of the set of current values ​​to corresponding phases of the other phases of the multi-phase electric machine, the set of current values ​​being determined based on a model of the multi-phase electric machine including the phase in the open circuit condition.

[0006] Another aspect of the disclosed embodiment includes a system for controlling a multi-phase electric machine. The system includes a processor and a memory. The memory includes instructions that, when executed by the processor, cause the processor to: determine a desired torque to be generated by the multi-phase electric machine in response to determining that a phase of the multi-phase electric machine is in an open circuit condition; retrieve a set of current values ​​to be applied to each of the other phases of the multi-phase electric machine to achieve the desired torque based on the determination that the phase is in the open circuit condition and the desired torque; and apply individual current values ​​of the set of current values ​​to corresponding phases of the other phases of the multi-phase electric machine, the set of current values ​​being determined based on a model of the multi-phase electric machine including the phase in the open circuit condition.

[0007] Another aspect of the disclosed embodiment includes an apparatus for controlling a multi-phase motor. The apparatus includes a processor and a memory. The memory includes instructions that, when executed by the processor, cause the processor to: determine a desired torque to be generated by the multi-phase motor in response to determining that a phase of the multi-phase motor is in an open circuit condition; retrieve a set of current values ​​to be applied to each of the other phases of the multi-phase motor to achieve the desired torque based on the determination that the phase is in the open circuit condition and the desired torque; and control torque pulsation corresponding to the phase in the open circuit condition by applying individual current values ​​of the current value set to corresponding phases of the other phases of the multi-phase motor, the current value set being determined based on a model of the multi-phase motor including the phase in the open circuit condition.

[0008] These and other aspects of the disclosure are disclosed in the following detailed description of the embodiments, the appended claims and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present disclosure is best understood by the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not drawn to scale. Instead, the sizes of the various features are arbitrarily expanded or reduced for clarity.

[0010] Figure 1 An electric power steering system according to the principles of the present disclosure is generally shown.

[0011] Figure 2 A controller according to the principles of the present disclosure is generally shown.

[0012] Figure 3A and Figure 3B A block diagram of a multi-phase motor controller in accordance with the principles of the present disclosure is generally shown.

[0013] Figure 4 is a flow chart generally illustrating a multi-phase motor control method according to the principles of the present disclosure. DETAILED DESCRIPTION

[0014] The following discussion is directed to various embodiments of the present disclosure. Although one or more of these embodiments may be preferred, the disclosed embodiments should not be interpreted or otherwise used as limiting the scope of the present disclosure, including the claims. In addition, it will be understood by those skilled in the art that the following description has a wide range of applications, and the discussion of any embodiment is intended only to be an exemplary discussion of that embodiment, and is not intended to imply that the scope of the present disclosure, including the claims, is limited to that embodiment.

[0015] As discussed above, vehicles such as automobiles, trucks, sport utility vehicles, crossovers, minivans, boats, aircraft, all-terrain vehicles, recreational vehicles, or other suitable vehicles often include one or more electric machines, such as electric motors, etc. For example, a vehicle may include one or more multi-phase electric machines configured to control various aspects of a steering system of the vehicle.

[0016] Multiphase electric machines (e.g., multiphase permanent magnet synchronous motors) can offer significant advantages over conventional machines, including improved efficiency, improved fault tolerance, and relatively low torque ripple (e.g., especially under fault conditions). As a result, such multiphase electric machines are increasingly used in safety-critical industrial applications, especially in the automotive and aerospace industries.

[0017] However, such multiphase motors may be susceptible to open circuit conditions (e.g., when one phase of the multiphase motor is in an open circuit condition). In such conditions, the current supplied to the operating phases of the multiphase motor may result in significant torque pulsation. Typically, control strategies for operating multiphase motors under open circuit conditions do not include a generalized mathematical model that describes the behavior of the open circuit condition. Furthermore, such control strategies are suboptimal and may include several redundant control parameters that require a significant amount of adjustment effort.

[0018] Therefore, it may be desirable to have systems and methods such as those described herein that are configured to control the operation of a multi-phase motor having a phase in an open circuit condition so as to maintain an average torque output while controlling (e.g., reducing or eliminating) torque pulsation. In some embodiments, the systems and methods described herein may be configured to provide a general control scheme for optimally controlling a multi-phase motor having a single phase in an open circuit condition. The systems and methods described herein may be configured to allow for maintaining a constant direct current (DC) torque of arbitrary magnitude while minimizing torque pulsation. The systems and methods described herein may be configured to include a model-based approach that allows for a reduction in tuning parameters (e.g., by using estimated parameters of the machine).

[0019] The systems and methods described herein can be configured to fully mitigate a single-phase open circuit condition by allowing operation in the open circuit condition to simulate the under (under) healthy (e.g., normal) operation. The systems and methods described herein can be applicable to all multi-phase synchronous machine configurations, including salient pole rotors and non-salient pole rotors as well as permanent magnet rotors and wound rotors.

[0020] In some embodiments, the systems and methods described herein can be configured to provide a generalized analytical model that describes the effects of an open circuit condition in a multi-phase permanent magnet synchronous motor (PMSM). The systems and methods described herein can be configured to use the model to develop a control strategy to optimally mitigate the open circuit condition (e.g., to obtain the maximum possible average torque and produce little to no torque ripple).

[0021] In some embodiments, the systems and methods described herein can be configured to provide a mathematical model that describes the behavior of a multiphase motor under open circuit conditions. The systems and methods described herein can be configured to utilize the model to develop a control scheme that produces an optimal torque output (e.g., a DC output with zero torque ripple only). The systems and methods described herein can be configured to provide a control scheme without additional adjustment parameters. The systems and methods described herein can be configured to allow modification of the torque command under open circuit conditions to maintain motor drive performance equivalent to a healthy state.

[0022] In some embodiments, the systems and methods described herein can be configured to determine a desired torque to be generated by the multiphase motor in response to determining that a phase of the multiphase motor is in an open circuit condition. The systems and methods described herein can be configured to retrieve a set of current values ​​to be applied to each of the other phases of the multiphase motor to achieve the desired torque based on the determination that the phase is in an open circuit condition and the desired torque. The systems and methods described herein can be configured to apply individual current values ​​in the set of current values ​​(e.g., by generating individual current commands and applying corresponding duty cycles based on the current commands) to corresponding phases in the other phases of the multiphase motor, the set of current values ​​being determined based on a model of the multiphase motor including the phase in the open circuit condition.

[0023] In some embodiments, the systems and methods described herein can be configured to control torque pulsations corresponding to torque generated by a multiphase motor in response to individual current values ​​of a current value set being applied to corresponding phases of other phases of the multiphase motor. In some embodiments, the multiphase motor includes a salient pole multiphase motor. In some embodiments, the multiphase motor includes a non-salient pole multiphase motor. In some embodiments, the multiphase motor includes a permanent magnet multiphase motor. In some embodiments, the multiphase motor includes a wound rotor. In some embodiments, the multiphase motor includes five phases. In some embodiments, the multiphase motor is associated with a steering system of a vehicle.

[0024] Figure 1An electric power steering system (EPS) 40 in accordance with the principles of the present disclosure is generally shown. The steering mechanism 36 comprises a rack and pinion type system and includes a toothed rack (not shown) within a housing 50 and a pinion (also not shown) located below a gear housing 52. When the operator input, hereinafter represented as the steering wheel 26 (e.g., hand wheel, etc.), is rotated, the upper steering shaft 29 is rotated and the lower steering shaft 51 connected to the upper steering shaft 29 by a universal joint 34 causes the pinion to rotate. The rotation of the pinion causes the rack to move, which moves the tie rods 38 (only one shown), which in turn moves the steering knuckles 39 (only one shown), which rotate the steerable wheel(s) 44 (only one shown).

[0025] Steering assistance is provided by a control device, indicated as a whole by reference numeral 24, and includes a controller 16 and an electric machine 19, which includes a permanent magnet synchronous motor and is hereinafter referred to as motor 19. The controller 16 is powered by a vehicle power supply 10 via line 12. The controller 16 receives a vehicle speed signal 14 representing the vehicle speed from a vehicle speed sensor 17. The steering angle is measured by a position sensor 32, which may be an optical encoding type sensor, a variable resistance type sensor, or any other suitable type of position sensor, and which provides a position signal 20 to the controller 16. The motor speed may be measured using a tachometer or any other device, and transmitted to the controller 16 as a motor speed signal 21. The motor speed, denoted as ω_m, may be measured, calculated, or a combination of measurement and calculation. For example, the motor speed ω_m may be calculated as a change in the motor position θ measured by the position sensor 32 over a specified time interval. For example, the motor speed ω_m can be determined as the derivative of the motor position θ according to the equation ω_m=Δθ / Δt, where Δt is the sampling time and Δθ is the change in position during the sampling interval. Alternatively, the motor speed can be derived from the motor position according to the rate of change of position with respect to time. It will be appreciated that there are many well-known methods for performing the function of the derivative.

[0026] As the steering wheel 26 is turned, the torque sensor 28 senses the torque applied to the steering wheel 26 by the vehicle operator. The torque sensor 28 may include a torsion bar (not shown) and a variable resistor type sensor (also not shown) that outputs a variable torque signal 18 to the controller 16 that is related to the amount of twist on the torsion bar. Although this is one type of torque sensor, any other suitable torque sensing device used with known signal processing techniques will suffice. In response to various inputs, the controller sends a command 22 to the electric motor 19, which provides torque assistance to the steering system through the worm 47 and worm gear 48, thereby providing torque assistance for vehicle steering.

[0027] It should be noted that while the disclosed embodiments are described with reference to motor control for electric steering applications, it will be understood that such references are illustrative only, and the disclosed embodiments may be applied to any motor control application employing an electric motor, e.g., steering, valve control, etc. In addition, the references and descriptions herein may be applicable to various forms of parameter sensors, including but not limited to torque, position, speed, etc. It should also be noted that hereinafter, for the sake of brevity and simplicity, references herein to electric machines, including but not limited to motors, will only refer to motors without limitation.

[0028] In the control system 24 as depicted, the controller 16 uses torque, position, speed, etc. to calculate (one or more) commands to deliver the required output power. The controller 16 is arranged to communicate with various systems and sensors of the motor control system. The controller 16 receives signals from each system sensor, quantizes the received information, and provides (one or more) output command signals in response thereto, in this case, for example, to the motor 19. The controller 16 is configured to develop (one or more) corresponding voltages output from an inverter (not shown), which can be optionally combined with the controller 16 and will be referred to as the controller 16 herein, so that when (one or more) corresponding voltages are applied to the motor 19, the desired torque or position is generated. In one or more examples, the controller 24 operates as a current regulator in a feedback control mode to generate the command 22. Alternatively, in one or more examples, the controller 24 operates in a feedforward control mode to generate the command 22. Because these voltages are related to the position and speed of the motor 19 and the desired torque, the position and / or speed of the rotor and the torque applied by the operator are determined. A position encoder is connected to the steering shaft 51 to detect the angular position θ. The encoder can sense the rotational position based on optical detection, magnetic field changes, or other methods. Typical position sensors include potentiometers, resolvers, synchronizers, encoders, etc., and combinations including at least one of the foregoing. The position encoder outputs a position signal 20, which indicates the angular position of the steering shaft 51 and thereby indicates the angular position of the motor 19.

[0029] The desired torque may be determined by one or more torque sensors 28 transmitting a torque signal 18 indicative of the applied torque. One or more exemplary embodiments include such a torque sensor 28 and the torque signal(s) 18 therefrom as they may be responsive to a flexible torsion bar, T-bar, spring, or similar device (not shown) configured to provide a response indicative of the applied torque.

[0030] In one or more examples, the temperature sensor(s) 23 are located at the motor 19. Preferably, the temperature sensor 23 is configured to directly measure the temperature of a sensing portion of the motor 19. The temperature sensor 23 transmits a temperature signal 25 to the controller 16 to facilitate the processing specified herein and to facilitate compensation. Typical temperature sensors include thermocouples, thermistors, thermostats, etc., and combinations including at least one of the foregoing sensors, which provide a calibratable signal proportional to a specific temperature when properly placed.

[0031] Position signal 20, speed signal 21, and (one or more) torque signal 18 are applied to controller 16. Controller 16 processes all input signals to generate values ​​corresponding to each signal, thereby obtaining rotor position values, motor speed values, and torque values ​​that can be used for processing in the algorithm specified in this article. It is usually also desirable to linearize, compensate, and filter the measurement signals such as those described above to enhance the characteristics of the acquired signal or eliminate undesirable characteristics of the acquired signal. For example, the signal can be linearized to increase the processing speed or to solve the large dynamic range of the signal. In addition, frequency or time-based compensation and filtering can be used to eliminate noise or avoid undesirable spectral characteristics.

[0032] In order to perform the specified functions and the desired processing, and the calculations therefor (e.g., identification of motor parameters, (one or more) control algorithms, etc.), the controller 16 may include, but is not limited to, (one or more) processors, (one or more) computers, (one or more) DSPs, memories, storage devices, (one or more) registers, timing, (one or more) interrupts, (one or more) communication interfaces, and input / output signal interfaces, etc., and combinations including at least one of the foregoing. For example, the controller 16 may include input signal processing and filtering to enable accurate sampling and conversion or acquisition of such signals from the vehicle's communication interface.

[0033] As described above, EPS 40 may be associated with a vehicle. The vehicle may include a plurality of controllers and / or electronic control units. Figure 2 , the vehicle may include a controller 100. The controller 100 may include any suitable controller. For example, the controller 100 may include features similar to the controller 16. The controller 100 may be configured to control, for example, various aspects of the vehicle (e.g., various aspects of the EPS 40 and / or other suitable features or components of the vehicle). The controller 100 may include a processor 102 and a memory 104.

[0034] The processor 102 may include any suitable processor, such as those described herein. Additionally or alternatively, the controller 100 may include any suitable number of processors in addition to or in addition to the processor 102. The memory 104 may include a single disk or multiple disks (e.g., a hard drive) and include a storage management module that manages one or more partitions within the memory 104. In some embodiments, the memory 104 may include flash memory, semiconductor (solid-state) memory, etc. The memory 104 may include a random access memory (RAM), a read-only memory (ROM), or a combination thereof. The memory 104 may include instructions that, when executed by the processor 102, cause the processor 102 to at least control various functions of the vehicle.

[0035] In some embodiments, the controller 100 can be configured to control various aspects of a motor (e.g., motor 19), such as Figure 3A and Figure 3B . Machine 19 may include a multi-phase motor. In some embodiments, as generally shown, machine 19 may include a five-phase PMSM controller. However, machine 19 may include any suitable number of phases. Additionally or alternatively, although machine 19 is generally shown and described as being associated with a vehicle and its systems, machine 19 may be configured to control or be operatively associated with any suitable application in addition to (or in addition to) controlling the vehicle (e.g., machine 19 may be used in any suitable application other than a vehicle, and the principles of the present disclosure may apply accordingly).

[0036] In some embodiments, machine 19 comprises a salient pole multiphase machine. In some embodiments, machine 19 comprises a non-salient pole multiphase machine. In some embodiments, machine 19 comprises a permanent magnet multiphase machine. In some embodiments, machine 19 comprises a wound rotor.

[0037] The current reference calculator 202 converts the torque command T c Converted into d / q current reference I dqc , the d / q current reference I dqc It is then sent to the current controller 206. The current controller 206 can be a feedback regulator using the current measurement results, or a feedforward compensator. The temperature T can be fed to the parameter compensator 204 to adjust the PMSM electrical parameters as needed. The current controller 206 then generates a duty cycle d for each phase through the duty cycle generator 210 of the power converter commutation module 208. ph In some embodiments, the d / q axis current references may be converted to phase current commands by applying an inverse reference frame transformation involving the measured electrical position θ r, and a feedback controller (e.g., a proportional-integral controller) is employed for each phase to generate a duty cycle for each phase.

[0038] Once the equivalent duty cycle d is generated for each phase ph , the pulse width modulator 212 generates an on-time t for different switches (eg, FETs) in the phase arm of the power converter (eg, inverter 216). ph The inverter 216 powered by the power source 214 then supplies the desired voltage to the motor (eg, PMSM 19), which generates a current I ph and electromagnetic torque T e Then measure the position θ r and current I ph The position is fed back to the position measuring device 220 and the current measuring device 222 of the control system to close the control loop. m Used together with the phase current to calculate the d / q measured current I dqm , which is used for closed-loop current control. Voltage source inverters (VSIs) are often used as power converters in PMSM-based electric drives.

[0039] Although the actual machine design and construction are different for three-phase PMSM and multi-phase (greater than three-phase) PMSM, for all these machines the same principles of vector control in a synchronous or d / q reference frame are possible by using appropriate transformation matrices to convert the phase currents and voltages into equivalent DC quantities in the synchronous coordinate frame.

[0040] Each of the five phases of the motor (e.g., PMSM 19) is connected to a phase leg consisting of two switches. For example, the inverter 216 includes five phase legs, each with two switches. The duty cycle (equivalent to the on time) of the upper switch and the lower switch is represented by d x and d x ', where x = a, b, c, d, e for the five phase arms. The voltage relative to ground is V xg (For example, the first phase arm is V ag , the second phase arm is V bg , etc.). These voltages V xg Controlled via the duty cycle calculated by the duty cycle generator 210 .

[0041] In some embodiments, the controller 100 can be configured to determine that a single phase of the machine 19 is in an open circuit condition. For example, each phase of the machine 19 can include a current sensor that communicates with the phase and / or is configured to measure the phase (e.g., each phase can include a current sensor). The controller 100 can monitor the current measurement results of each current sensor. If the controller 100 turns on the corresponding phase and receives a current measurement result indicating that no current is detected in the phase, the controller 100 can determine that the phase is in an open circuit condition. It should be understood that the controller 100 can use any suitable technology to determine that the phase is in an open circuit condition. The controller 100 can determine the desired torque to be generated by the machine 19 based at least on the input received from, for example, a hand wheel of the steering system of the vehicle. It should be understood that the controller 100 can receive input indicating the desired output torque of the machine 19 from any suitable component in any suitable manner.

[0042] The controller 100 can retrieve a set of current values ​​to be applied to each of the working phases of the machine 19 based on which phase is in an open circuit condition and the desired torque. For example, the controller 100 can access a database or table configured to store sets of current values ​​associated with the desired torque (e.g., or torque range) and the corresponding open circuit condition. The database or table can include any suitable database or table and can be located remotely from the vehicle, located immediately within the vehicle, or located in any suitable location.

[0043] The set of current values ​​may be a predetermined set of current values ​​that, when applied to the working phases of the machine 19, causes the machine 19 to output a desired torque with reduced or no torque ripple. The set of current values ​​may be predetermined and programmed and / or stored in the database or table (e.g., in a database or table) during manufacture of the machine 19, or may be programmed and / or stored in the database or table periodically during use of the machine 19 (e.g., over a period of use).

[0044] In some embodiments, the set of current values ​​stored in the database or table may be determined by a computing device (e.g., a laptop computing device, a mobile computing device, a desktop computing device, a server computing device, or any suitable computing device). During normal or healthy operation (e.g., when all phases of machine 19 are operating), the model of machine 19 may be described according to the following equation:

[0045]

[0046] in, represents the actual motor torque output under healthy conditions, p is the number of magnetic pole pairs, and λ m is the permanent magnet (PM) flux, m is the total number of phases, k represents different phases, Iq is the actual q-axis motor current, and q is an integer with a value between 1 and 5.

[0047] During open circuit conditions, the model of the machine 19 can be described according to the following equation:

[0048]

[0049]

[0050]

[0051]

[0052] in, is the actual torque output under open circuit conditions, and and are the average component and pulsating component of torque output, I d is the actual d-axis motor current, and r represents an integer associated with the particular phase that is open circuited (eg, r may be equal to 0 for the first phase, 1 for the second phase, and so on).

[0053] Using the foregoing equation, the computing device may be configured to Figure 3B At 226, generally shown in FIG. 1 , a current command set is determined and applied to achieve a desired current value, which can produce a desired torque output. The current command can be used to generate a corresponding duty cycle, which when applied to the phase of the machine 19, produces a desired current value at each corresponding phase. The computing device can determine different current value sets for different phases in an open circuit condition. Additionally or alternatively, the computing device can adjust the current value set based on various desired torque amounts. The computing device can store multiple current value sets, each of which corresponds to a corresponding phase (e.g., a corresponding phase in an open circuit condition) for a corresponding desired torque amount or desired torque range. In some embodiments, the current value set can be selectively adjusted by an operator of the computing device to obtain a desired response from the machine 19.

[0054] The computing device may modify each of a plurality of current command sets (eg, to produce a desired current value and may be referred to herein as a current value set) in order to eliminate (eg, or significantly reduce) torque ripple associated with the current command value set according to the following formula:

[0055]

[0056]

[0057]

[0058]

[0059] In some embodiments, Figure 3B At the current controller 206 shown generally in FIG. 1 , the d / q axis current references may be converted to phase current commands by applying an inverse reference frame transformation involving the measured electrical position θ r , and a feedback controller (e.g., a proportional-integral controller) is employed for each phase to generate a duty cycle for each phase.

[0060] The model of the final average torque (eg, in response to the above equation being applied) may be described according to the following equation:

[0061]

[0062] The computing device can be Figure 3B At 224 shown generally in FIG. 1 , a modified torque command in the open phase state is determined according to the following equation to maintain the original commanded torque:

[0063]

[0064] It should be noted that maintaining the original commanded torque is only an example, and the computing device can modify the torque command in the open phase state to achieve any suitable commanded torque. As described, the computing device can store multiple current value sets in a database or table for access by the controller 100. As described, the controller 100 can retrieve a current value set to be applied to each of the other phases of the machine 19 to achieve the desired torque based on determining which phase is in an open circuit condition and the desired torque. The controller 100 can apply the individual current values ​​of the current value set to the corresponding phases of the other phases of the machine. For example, the controller 100 can apply the first current in the current value set to the first working phase of the machine 19, the second current value in the current value set to the second working phase of the machine 19, and so on for each working phase of the machine 19.

[0065] In response to controller 100 applying the current value set to the working phases of machine 19, machine 19 can produce the desired torque. Additionally or alternatively, torque ripples produced by machine 19 (e.g., in response to each phase being in an open circuit condition) can be controlled (e.g., eliminated or significantly reduced) based on controller 100 applying the current value set to the working phases of machine 19.

[0066] In some embodiments, the controller 100 can perform the methods described herein. However, the methods described herein performed by the controller 100 are not meant to be limiting, and thus any type of software executed on a controller or processor can perform the methods described herein without departing from the scope of the present disclosure. For example, a controller (e.g., a processor executing software within a computing device) can perform the methods described herein.

[0067] Figure 4 1 is a flow chart generally illustrating a multi-phase electric machine control method 300 according to the principles of the present disclosure. At 302, the method 300 determines a desired torque to be generated by the multi-phase electric machine 19 in response to determining that a phase of the multi-phase electric machine is in an open circuit condition. For example, the controller 100 determines the desired torque to be generated by the machine 19.

[0068] At 304, method 300 retrieves a set of current values ​​to be applied to each of the other phases of the multi-phase electric machine to achieve the desired torque based on determining that the phase is in an open circuit condition and the desired torque. For example, controller 100 retrieves a set of current values ​​to be applied to the working phases of machine 19 to achieve the desired torque.

[0069] At 306, the method 300 applies each current value of the current value set to a corresponding phase in other positions of the multi-phase electric machine, the current value set being determined based on a model of the multi-phase electric machine including a phase in an open circuit condition. For example, the controller 100 applies the current value of the current value set to a corresponding working phase in the working phase of the machine 19. The controller 100 can control the torque ripple of the machine 19 by applying the current value set to the working phase of the machine 19.

[0070] In some embodiments, a method for controlling a multi-phase electric machine includes: in response to determining that a phase of the multi-phase electric machine is in an open circuit condition, determining a desired torque to be generated by the multi-phase electric machine, and retrieving a set of current values ​​to be applied to each of the other phases of the multi-phase electric machine to achieve the desired torque based on the determination that the phase is in the open circuit condition and the desired torque. The method may also include: applying individual current values ​​of the set of current values ​​to corresponding phases of the other phases of the multi-phase electric machine, the set of current values ​​determined based on a model of the multi-phase electric machine including the phase in the open circuit condition.

[0071] In some embodiments, applying the individual current values ​​of the current value set to corresponding phases in other phases of the multi-phase motor can control torque pulsations corresponding to torque, which is generated by the multi-phase motor in response to the individual current values ​​of the current value set being applied to corresponding phases in other phases of the multi-phase motor. In some embodiments, the multi-phase motor includes a salient pole multi-phase motor. In some embodiments, the multi-phase motor includes a hidden pole multi-phase motor. In some embodiments, the multi-phase motor includes a permanent magnet multi-phase motor. In some embodiments, the multi-phase motor includes a wound rotor. In some embodiments, the multi-phase motor includes five phases. In some embodiments, the multi-phase motor is associated with a steering system of a vehicle.

[0072] In some embodiments, a system for controlling a multi-phase electric machine includes a processor and a memory. The memory includes instructions that, when executed by the processor, cause the processor to: determine a desired torque to be generated by the multi-phase electric machine in response to determining that a phase of the multi-phase electric machine is in an open circuit condition; retrieve a set of current values ​​to be applied to each of the other phases of the multi-phase electric machine to achieve the desired torque based on the determination that the phase is in the open circuit condition and the desired torque; and apply individual current values ​​of the set of current values ​​to corresponding phases of the other phases of the multi-phase electric machine, the set of current values ​​being determined based on a model of the multi-phase electric machine including the phase in the open circuit condition.

[0073] In some embodiments, the instructions further cause the processor to: control a torque pulsation corresponding to a torque generated by the multi-phase motor in response to individual current values ​​of the current value set being applied to corresponding phases of other phases of the multi-phase motor. In some embodiments, the multi-phase motor includes a salient pole multi-phase motor. In some embodiments, the multi-phase motor includes a non-salient pole multi-phase motor. In some embodiments, the multi-phase motor includes a permanent magnet multi-phase motor. In some embodiments, the multi-phase motor includes a wound rotor. In some embodiments, the multi-phase motor includes five phases. In some embodiments, the multi-phase motor is associated with a steering system of a vehicle.

[0074] In some embodiments, a device for controlling a multi-phase motor includes a processor and a memory. The memory includes instructions that, when executed by the processor, cause the processor to: determine a desired torque to be generated by the multi-phase motor in response to determining that a phase of the multi-phase motor is in an open circuit condition; retrieve a current value set to be applied to each of the other phases of the multi-phase motor to achieve the desired torque based on the determination that the phase is in the open circuit condition and the desired torque; and control torque pulsation corresponding to the open circuit condition by applying individual current values ​​of the current value set to corresponding phases of the other phases of the multi-phase motor, the current value set being determined based on a model of the multi-phase motor including the phase in the open circuit condition.

[0075] In some embodiments, the multiphase motor comprises five phases. In some embodiments, the multiphase motor comprises a salient pole multiphase motor. In some embodiments, the multiphase motor comprises a non-salient pole multiphase motor.

[0076] The above discussion is intended to illustrate the principles and various embodiments of the present disclosure. Once the above disclosure is fully understood, many changes and modifications will become apparent to those skilled in the art. It is intended that the following claims be interpreted to include all such changes and modifications.

[0077] It should be noted that the various technical features described herein facilitate improvements to motor control systems. The description herein uses an electric power steering system (EPS) as an example of using a motor control system, and the various technical features described herein are used and / or implemented to improve the motor control system. However, the technical solutions described herein are not limited to electric power steering systems, but are applicable to motor control systems used in any other system (e.g., industrial motors, biomechanical devices, autonomous driving assistance systems, or any other motors using motor control systems).

[0078] The word "example" is used herein to mean used as an example, instance or illustration. Any aspect or design described herein as an "example" is not necessarily to be interpreted as being more preferred or advantageous than other aspects or designs. On the contrary, the use of the word "example" is intended to present the concept in a specific way. As used in this application, the term "or" is intended to represent an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clearly seen from the context, "X includes A or B" is intended to represent any natural inclusive arrangement. That is, if X includes A; X includes B; or X includes both A and B, then "X includes A or B" is satisfied in any of the foregoing cases. In addition, the article "a / an" used in this application and the appended claims should generally be interpreted as meaning "one or more", unless otherwise specified or clearly pointed to the singular form from the context. In addition, unless so described, the use of the term "embodiment" or "one embodiment" throughout the text is not intended to represent the same embodiment or embodiment.

[0079] The implementation of the systems, algorithms, methods, instructions, 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 circuit. In the claims, the term "processor" shall be understood to include any of the foregoing hardware, alone or in combination. The terms "signal" and "data" are used interchangeably.

[0080] As used herein, the term module may include a packaged functional hardware unit designed for use with other components, a set of instructions executable by a controller (e.g., a processor executing software or firmware), a processing circuit configured to perform a specific function, and a self-contained hardware or software component that interfaces with a larger system. For example, a module may include an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), an electrical circuit, a digital logic circuit, an analog circuit, a combination of discrete circuits, gate circuits, and other types of hardware, or a combination thereof. In other embodiments, a module may include a memory that stores instructions executable by a controller to implement the features of the module.

[0081] Furthermore, in one aspect, for example, the systems described herein may be implemented using a general purpose computer or general purpose processor with a computer program that, when executed, performs any corresponding method, algorithm, and / or instruction described herein. Additionally or alternatively, for example, a special purpose computer / processor may be utilized that may include other hardware for performing any method, algorithm, or instruction described herein.

[0082] In addition, all or part of the 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 device that can tangibly contain, store, communicate, or transport a program for use by or in conjunction with any processor. The medium may be, for example, an electronic, magnetic, optical, electromagnetic device, or a semiconductor device. Other suitable media may also be used.

[0083] The above embodiments, implementations and aspects have been described to allow easy understanding of the present disclosure and are not intended to limit the present disclosure. On the contrary, the present disclosure is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which scope should be given the broadest interpretation to cover all such modifications and equivalent structures permitted by law.

Claims

1. A method for controlling a multi-phase motor, the method comprising: In response to determining that a phase of the multi-phase electric machine is in an open circuit condition, determining a desired torque to be generated by the multi-phase electric machine; retrieving a set of current values ​​to be applied to each of the other phases of the multi-phase electric machine to achieve the desired torque based on determining that the phase is in the open circuit condition and the desired torque; as well as Individual current values ​​of the set of current values ​​are applied to corresponding phases of other phases of the multi-phase electric machine, the set of current values ​​being determined based on a model of the multi-phase electric machine including the phase in the open circuit condition.

2. The method according to claim 1, wherein: The operation of applying each current value of the current value set to a corresponding phase among the other phases of the multi-phase motor controls a torque pulsation corresponding to a torque generated by the multi-phase motor in response to each current value of the current value set being applied to a corresponding phase among the other phases of the multi-phase motor.

3. The method according to claim 1, wherein: The multi-phase electric machine comprises a salient-pole multi-phase electric machine.

4. The method according to claim 1, wherein: The multi-phase motor includes a non-salient-pole multi-phase motor.

5. The method according to claim 1, wherein: The multi-phase electric machine comprises a permanent magnet multi-phase electric machine.

6. The method according to claim 1, wherein: The multi-phase electric machine includes a wound rotor.

7. The method according to claim 1, wherein: The multi-phase electric machine comprises five phases.

8. The method according to claim 1, wherein: The multi-phase electric machine is associated with a steering system of a vehicle.

9. A system for controlling a multi-phase motor, the system comprising: processor; as well as a memory comprising instructions which, when executed by the processor, cause the processor to: In response to determining that a phase of the multi-phase electric machine is in an open circuit condition, determining a desired torque to be generated by the multi-phase electric machine; retrieving a set of current values ​​to be applied to each of the other phases of the multi-phase electric machine to achieve the desired torque based on determining that the phase is in the open circuit condition and the desired torque; as well as Individual current values ​​of the set of current values ​​are applied to corresponding phases of other phases of the multi-phase electric machine, the set of current values ​​being determined based on a model of the multi-phase electric machine including the phase in the open circuit condition.

10. The system according to claim 9, wherein: The instructions further cause the processor to control a torque ripple corresponding to torque generated by the multi-phase motor in response to respective current values ​​of the set of current values ​​being applied to corresponding ones of the other phases of the multi-phase motor.

11. The system according to claim 9, wherein: The multi-phase electric machine comprises a salient-pole multi-phase electric machine.

12. The system according to claim 9, wherein: The multi-phase motor includes a non-salient-pole multi-phase motor.

13. The system according to claim 9, wherein: The multi-phase electric machine comprises a permanent magnet multi-phase electric machine.

14. The system according to claim 9, wherein: The multi-phase electric machine includes a wound rotor.

15. The system according to claim 9, wherein: The multi-phase electric machine comprises five phases.

16. The system of claim 9, wherein: The multi-phase electric machine is associated with a steering system of a vehicle.

17. A device for controlling a multi-phase motor, the device comprising: processor; as well as a memory comprising instructions which, when executed by the processor, cause the processor to: In response to determining that a phase of the multi-phase electric machine is in an open circuit condition, determining a desired torque to be generated by the multi-phase electric machine; retrieving a set of current values ​​to be applied to each of the other phases of the multi-phase electric machine to achieve the desired torque based on determining that the phase is in the open circuit condition and the desired torque; as well as The torque pulsation corresponding to the open circuit condition is controlled by applying each current value of the current value set to a corresponding phase among other phases of the multi-phase motor, the current value set being determined based on a model of the multi-phase motor including the phase in the open circuit condition, the multi-phase motor being associated with a steering system of a vehicle.

18. The device according to claim 17, wherein: The multi-phase electric machine comprises five phases.

19. The device according to claim 17, wherein: The multi-phase electric machine comprises a salient-pole multi-phase electric machine.

20. The device according to claim 17, wherein: The multi-phase motor includes a non-salient-pole multi-phase motor.

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