Motor control method and system, computer storage medium and program product

Abstract

The present application relates to a motor control method and system, a computer storage medium and a program product, the motor control method comprising: inputting a difference between a set value of an input current of a motor and a coordinate transformed measured value of the input current into a proportional resonant controller, the input current comprises a D-axis current component and a Q-axis current component in a two-phase rotating coordinate system; and generating an inverter control signal with the proportional resonant controller to regulate the input current, where a resonant frequency of the proportional resonant controller is determined based on a frequency of the D-axis current component.

Description

Technical Field

[0001] The present application relates to the field of motor control, and more particularly, to a motor control method and system, a computer storage medium, and a program product. Background Art

[0002] In a solution for heating a battery pack using an alternating pulse current, an alternating pulse current is generated through the inductive current continuation effect of a vehicle motor system and the control of a switching element. Since the battery has an internal resistance, the heat generated when the pulse current flows through the internal resistance is used to heat the battery pack to an appropriate temperature. However, in this solution, it may not be considered that when the pulse current changes at a high frequency, traditional PID control may be difficult to track the continuous change of the command for configuring the pulse current, reducing the stability of motor control.

[0003] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present application, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0004] According to an aspect of the present application, there is provided a motor control method, the motor control method including: inputting a difference between a set value of an input current of a motor and a measured value of the input current after coordinate transformation into a proportional-resonant controller, where the input current includes a D-axis current component and a Q-axis current component in a two-phase rotating coordinate system; and using the proportional-resonant controller to generate an inverter control signal to adjust the input current, where the resonant frequency of the proportional-resonant controller is determined based on the frequency of the D-axis current component.

[0005] In one or more embodiments of the present application, optionally, the motor control method further includes: generating the inverter control signal by performing space vector pulse width modulation on an α-axis voltage component and a β-axis voltage component output by the proportional-resonant controller.

[0006] In one or more embodiments of the present application, optionally, the transfer function of the proportional-resonant controller includes a cut-off frequency, and the cut-off frequency is determined according to the resonant frequency of the proportional-resonant controller.

[0007] In one or more embodiments of the present application, optionally, the set value of the D-axis current component changes within a period corresponding to the frequency of the D-axis current component, and the set value of the Q-axis current component is zero.

[0008] In one or more embodiments of the present application, optionally, the motor includes at least a permanent magnet synchronous motor, and the coordinate transformation includes at least a Clarke transformation.

[0009] According to one aspect of the present application, there is provided a motor control system, the motor control system comprising: a processor; and a memory storing instructions executable on the processor, the execution of the instructions on the processor causing the following operations: inputting the difference between the set value of the input current of the motor and the measured value of the input current after coordinate transformation into a proportional-resonant controller, wherein the input current includes a D-axis current component and a Q-axis current component in a two-phase rotating coordinate system; and generating an inverter control signal by using the proportional-resonant controller to adjust the input current, wherein the resonant frequency of the proportional-resonant controller is determined based on the frequency of the D-axis current component.

[0010] In one or more embodiments of the present application, optionally, the operation further includes: generating the inverter control signal by performing space vector pulse width modulation on the α-axis voltage component and the β-axis voltage component output by the proportional-resonant controller.

[0011] In one or more embodiments of the present application, optionally, the transfer function of the proportional-resonant controller includes a cut-off frequency, and the cut-off frequency is determined according to the resonant frequency of the proportional-resonant controller.

[0012] In one or more embodiments of the present application, optionally, the set value of the D-axis current component changes within a period corresponding to the frequency of the D-axis current component, and the set value of the Q-axis current component is zero.

[0013] In one or more embodiments of the present application, optionally, the motor at least includes a permanent magnet synchronous motor, and the coordinate transformation at least includes a Clarke transformation.

[0014] According to one aspect of the present application, there is provided a computer-readable storage medium storing computer instructions, which when executed by a processor, cause any of the above-mentioned motor control methods to be implemented.

[0015] According to one aspect of the present application, there is provided a computer program product including a computer program, which when executed by a processor, implements any of the above-mentioned motor control methods. Description of the Drawings

[0016] When reading the following detailed description with reference to the accompanying drawings, the above and other features, aspects and advantages of the present application will be better understood, in which the same or similar units are denoted by the same reference numerals. It should be noted that the drawings in the present application are merely schematic and may not be drawn to scale or specific quantities. In the drawings:

[0017] Figure 1It is a flowchart of a motor control method according to some embodiments of the present application;

[0018] Figure 2 It is a schematic diagram depicting a motor control process according to some embodiments of the present application;

[0019] Figure 3 It is a schematic diagram depicting another motor control process according to some embodiments of the present application;

[0020] Figure 4 It is a schematic block diagram of a motor control system according to some embodiments of the present application. Detailed implementation manners

[0021] The present application will be more comprehensively described below with reference to the accompanying drawings which illustrate schematic embodiments of the present application. In the following detailed description of the embodiments, many specific details are set forth in order to provide a more thorough understanding of the disclosed content of the present application. However, in one or more embodiments, well-known features are not described in detail to avoid unnecessarily complicating the description. Where applicable, the embodiments of the present application and the features in the embodiments may also be combined with each other.

[0022] In the present application, terms such as "including", "comprising", "having", etc. indicate that in addition to the units and steps directly and clearly stated in the description and claims, the technical solutions recorded in the present application do not exclude the existence of other units and steps that are not directly or clearly stated.

[0023] In some schemes for heating a battery pack using an alternating pulse current, the direct current output by the battery pack passes through, for example, an inverter to provide input current for the motor, and through the inductive current continuation effect of the motor and the control of the switching element, the motor can reversely provide charging current for the battery pack. Thus, the formed alternating pulse current causes heat to be generated on the internal resistance of the battery, causing the temperature of the battery pack to rise. In the above scheme, the motor controller adjusts the input current of the motor via the inverter according to the received current control command. When the pulse current changes at a high frequency (for example, greater than 50 Hz), the motor control command for adjusting the input current of the motor also changes simultaneously.

[0024] However, traditional PID (Proportion Integral Differential) control may be difficult to track such commands (for example, the continuously changing input current set value included in the command), thereby reducing the stability of motor control. The present application proposes to utilize the high-gain characteristic of the proportional resonant controller at the high-frequency resonant point to track the continuous change of the command for configuring the high-frequency pulse current.

[0025] A control command for changing the input current of the motor (e.g., from an upper controller) can be received by the motor controller, and the motor controller can generate a set value of the input current according to the control command. As recognized by those skilled in the art, vector control is a typical means for controlling an AC motor, which converts a three-phase time-varying system into, for example, a two-phase non-time-varying system via a coordinate transformation, so that the torque and excitation current can be controlled in a manner similar to that of controlling a DC motor.

[0026] The following will refer to Figures 1 to 3 to illustrate the embodiments of the present application. Figure 1 Fig. 100 shows a motor control method according to some embodiments of the present application. Method 100 includes steps 110 and 120. In step 110, the difference between the set value of the input current of the motor and the coordinate-transformed measured value of the input current is input to a proportional-resonant controller. In some embodiments, the above set value may include the set values of the D-axis current component and the Q-axis current component that are perpendicular to each other in a two-phase rotating coordinate system.

[0027] By using the set values of the D-axis current component and the Q-axis current component respectively, the control of the three-phase alternating current can be converted into two-phase vector control in a two-phase rotating coordinate system to control the generation of the excitation current and torque respectively. In some embodiments, the Q-axis current component for generating torque can be set to zero so that no torque appears on the Q-axis of the motor, thereby avoiding vehicle vibration caused by the torque generated by the Q-axis current component on the motor when the vehicle is in a stationary state for heating the battery (e.g., parking). In some embodiments, the set value of the D-axis current component can be changed according to the difference between the desired heating temperature and the actual temperature of the battery, the expected heating duration, or both, to adjust the magnitude of the alternating pulse current induced in the battery pack.

[0028] In step 120, an inverter control signal can be generated by using the proportional-resonant controller to adjust the input current. In some embodiments, the resonant frequency of the proportional-resonant controller can be set based on the frequency of the D-axis current component. In some embodiments, the set frequency of the D-axis current component can be adjusted according to the polarization characteristics of the battery cells in the battery pack (e.g., the change of the polarization voltage during the heating process).

[0029] The following will specifically illustrate steps 110 and 120 in conjunction with Figure 2 and Figure 3 Fig. 200 is a schematic diagram depicting a motor control process according to some embodiments of the present application. To avoid making the present disclosure overly lengthy and complex, some well-known features have been omitted.

[0030] Figure 2 Fig. 200 is a schematic diagram depicting a motor control process 200 according to some embodiments of the present application. To avoid making the present disclosure overly lengthy and complex, some well-known features have been omitted. Figure 2The differences between the motor control process shown and traditional PID control include improving the PI or PID controller to a proportional-resonant controller. The pulse-width modulation (PWM) signal output via sub-processes 210 to 250 is received by the inverter 260, and then the control of the motor 270 can be achieved by controlling the input current of the three-phase windings, where the motor 270 can be a permanent magnet synchronous motor. It should be noted that, where applicable, the corresponding functions of sub-processes 210 to 250 of the motor control process 200 provided by this application can be implemented using hardware, software, or a combination of hardware and software, and where applicable, they can be combined with each other and serially and / or parallelly executed by the motor controller.

[0031] First, in sub-process 210, the D-axis current component and the Q-axis current components I d and I q The respective set values and the measured values of the current input to the motor 270 as feedback are input to the comparator. Specifically, I d can be a periodically varying signal (e.g., in the form of a sine wave, triangular wave) with a magnitude between zero and a certain negative value (e.g., 200 A), while I q can be set to zero. In some embodiments, the measured values of the input currents I a_f 、I b_f and I c_f of the three-phase windings of the motor 270 are respectively input to the comparator via the coordinate transformation occurring in sub-process 250. In the embodiment described with reference to Figure 2 The above-mentioned coordinate transformation occurring in sub-process 250 may include Park transformation and Clarke transformation, transforming I a_f 、I b_f and I c_f into I d_f and I q_f in the two-phase rotating coordinate system.

[0032] Next, turning to sub-process 220, the values of I d_f and I q_f are respectively input to the proportional-resonant controller with the differences between the set values of the D-axis current component and the Q-axis current components I d and I q . The transfer functions G1 of the ideal proportional-resonant controller and G2 of the non-ideal proportional-resonant controller are respectively expressed as follows:

[0033]

[0034] where, K p represents the proportional gain, K i represents the integral gain, ω0 represents the resonant frequency (e.g., the angular frequency of the input current), and ωc represents the cut-off frequency of the proportional-resonant controller for determining the frequency bandwidth (i.e., ω0 ± ω c ). The proportional-resonant controller has a gain (theoretically positive infinity) at the frequency ω0 that is much higher than the gains at other frequencies, thus achieving a steady-state error-free tracking of a signal having the same value as the frequency ω0 (which can be the D-axis current component in this application).

[0035] Since it is difficult to achieve a perfect equality between the frequency ω0 and the frequency of the signal in actual control, and compared with ω0, the gain of the ideal proportional-resonant controller at other frequencies will show a severe attenuation. Thus, compared with the ideal proportional-resonant controller, the magnitude of ω c introduced in the non-ideal proportional-resonant controller can be adjusted so that the gain of the proportional-resonant controller at frequencies different from ω0 will not be significantly attenuated, thereby expanding the bandwidth of the proportional-resonant controller and contributing to ensuring the stability of the control system. In some embodiments, the cut-off frequency ω c is determined according to the resonant frequency ω0. For example, considering the combination of stability and steady-state error-free tracking, ω c can be set such that 1 / 5ω0 ≤ ω c ≤ 1 / 3ω0.

[0036] The output signal obtained via the proportional-resonant controller may include the D- and Q-axis voltage set values of the motor (which can also be referred to as the dq-axis voltage commands) for driving the input current to converge to the target values (i.e., the set values of I d and I q ) and achieving the tracking of the set value of the D-axis current component that varies with the period T = 2π / ω0. Since in the space vector pulse width modulation (SVPWM) algorithm, the switching control signal for the inverter 260 is calculated based on the voltage components in the α, β axes rather than the D, Q-axis voltage components, these voltage commands are converted into the α, β-axis voltage set values in the two-phase stationary coordinate system (similarly, can be called the αβ-axis voltage commands) via the inverse Park transformation that occurs in the sub-process 230.

[0037] Next, similar to the traditional PID control method, the SVPWM that occurs in the sub-process 240 generates the switching control signal for the inverter 260 to adjust the voltage applied to the motor 270 by changing the on and off states of the switching elements (such as IGBTs) of the inverter 260, so that I d_f and I q_f tend to the set values I d and I q .

[0038] Figure 3 is a schematic diagram depicting another motor control process according to some embodiments of the present application. As Figure 3As shown, the pulse-width modulation (PWM) signal output via sub-processes 310 to 350 is received by the inverter 360, and then the control of the motor 370 can be achieved by controlling the input current of the three-phase winding. Among them, sub-processes 310 to 340, inverter 360, and motor 370 can be respectively the sub-processes 210 to 240, inverter 260, and motor 270 as shown in Figure 2 . For the Figure 3 described motor control process and the Figure 2 shown motor control process, the difference lies in that the real-time measurement values of the input currents I a_f , I b_f , and I c_f of the three-phase winding after single coordinate transformation and the set values of the D-axis and Q-axis current components I d and I q after coordinate transformation are jointly input into the comparator.

[0039] In sub-process 330, the set values of I d and I q respectively undergo coordinate transformation, such as inverse Park transformation, to generate the corresponding current representations I d and I q of I α and I β in the two-phase stationary coordinate system. Correspondingly, in sub-process 350, the input currents I a_f , I b_f , and I c_f undergo coordinate transformation, such as Clarke transformation, to generate the corresponding current representations I a_f , I b_f , and I c_f of I α_f and I β_f in the two-phase stationary coordinate system.

[0040] In sub-process 310, the corresponding values of I α and I β with I α_f and I β_f are input into the comparator. Here, since the proportional-resonant controller can operate on the received difference in the two-phase stationary coordinate system without the subsequent coordinate transformation from the stationary coordinate system to the rotating coordinate system, at least compared with the traditional PID control method, the proportional-resonant control method provided in the embodiment described with Figure 3 can omit the Park transformation that occurs in sub-process 250 (and, when the set values of I d and I q do not change, further omit the inverse Park transformation that occurs in sub-process 330), saving the calculation cost.

[0041] Go to sub - process 320, I α_f and I β_f The values of and I α and I β respectively, and the differences between the set values of the D - axis current component and the Q - axis current component I Figure 2 are input into a proportional - resonant controller (e.g., the proportional - resonant controller described with reference to Figure 2 ). The output signal obtained via the proportional - resonant controller includes the α, β - axis voltage set values of the motor, and in a manner similar to that described for Figure 2 , in the next sub - process 340, the SVPWM can generate the switching control signal of the inverter 360 according to these set values, so as to adjust the voltage applied to the motor 370 by changing the on - and - off states of the switching elements (e.g., IGBTs) of the inverter 360, such that I α_f and I β_f tend to I α and I β .

[0042] Figure 4 is a schematic block diagram of a motor control system 400 according to some embodiments of the present application. As Figure 4 shown, the motor control system 400 includes at least one memory 410 (e.g., non - volatile memory such as flash memory, ROM, hard disk drive, magnetic disk, optical disk, etc.), at least one processor 420, and stored instructions 430. The memory 410 stores instructions 430 that can be executed by the processor 420. The processor 420 is configured to run the instructions 430 stored on the memory 410. By running a computer program stored on one or more memories on one or more processors (e.g., in a manner where multiple processors cooperate to run the computer program or a single processor runs the computer program alone), one or more steps or operations included in the method described above with the aid of Figures 1 to 3 can be implemented.

[0043] According to another aspect of the present application, there is also provided a computer - readable storage medium, on which computer instructions are stored, and when the computer instructions are executed by a processor, one or more steps or operations included in the method described above with the aid of Figures 1 to 3 can be implemented.

[0044] According to another aspect of the present application, there is also provided a computer program product, which includes a computer program, and when the computer program is executed by a processor, one or more steps or operations included in the method described above with the aid of Figures 1 to 3 can be implemented.

[0045] The processor referred to in the present application may be an integrated circuit chip with signal - processing capabilities. In the implementation process, with the aid of Figures 1 to 3One or more steps or operations included in the described method can be completed by the integrated logic circuit of the hardware in the processor or by instructions in the form of software. The above-mentioned processor can be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc.

[0046] As used in this application, the computer-readable storage medium includes various types of computer storage media and can be any available medium accessible by a general-purpose or special-purpose computer. For example, the computer-readable storage medium can include RAM, ROM, EPROM, E2PROM, registers, hard disks, removable disks, CD-ROMs, or other optical disk memories, magnetic disk memories, or other magnetic storage devices, or any other transient or non-transient medium capable of carrying or storing desired program code units in the form of instructions or data structures and accessible by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. The above combinations should also be included within the scope of protection of the computer-readable storage medium. An exemplary storage medium is coupled to the processor so that the processor can read from / write to the storage medium. In an alternative, the storage medium can be integrated into the processor.

[0047] It should be noted that the embodiments described in this application are intended to make the disclosure herein comprehensive and complete and are not intended to limit the scope of the claimed subject matter. Those skilled in the art can think of other feasible changes or substitutions based on the technical scope disclosed in this application, and such changes or substitutions are all covered by the protection scope of this application. Those skilled in the art will know that the above description and examples are provided only for the convenience of illustration and example, and the described description and examples are not intended to cover all aspects of this application or limit this application to the precise form disclosed. The technical solutions described in this application can be implemented in different forms without departing from the spirit and scope of this application.

Claims

1. A motor control method, the motor control method comprising: inputting a difference between a set value of an input current of a motor and a measured value of the input current after coordinate transformation into a proportional-resonant controller, wherein the input current includes a D-axis current component and a Q-axis current component in a two-phase rotating coordinate system; and using the proportional-resonant controller to generate an inverter control signal to regulate the input current, wherein a resonant frequency of the proportional-resonant controller is determined based on a frequency of the D-axis current component.

2. The motor control method according to claim 1, further comprising: generating the inverter control signal by performing space vector pulse width modulation on an α-axis voltage component and a β-axis voltage component output by the proportional-resonant controller.

3. The motor control method according to claim 1, wherein, A transfer function of the proportional-resonant controller includes a cut-off frequency, and the cut-off frequency is determined according to the resonant frequency of the proportional-resonant controller.

4. The motor control method according to claim 1, wherein, The set value of the D-axis current component varies within a period corresponding to the frequency of the D-axis current component, and the set value of the Q-axis current component is zero.

5. The motor control method according to claim 1, wherein, The motor includes at least a permanent magnet synchronous motor, and the coordinate transformation includes at least a Clarke transformation.

6. A motor control system, the motor control system comprising: a processor; and a memory storing instructions executable on the processor, the execution of the instructions on the processor causing the following operations: inputting a difference between a set value of an input current of a motor and a measured value of the input current after coordinate transformation into a proportional-resonant controller, wherein the input current includes a D-axis current component and a Q-axis current component in a two-phase rotating coordinate system; and using the proportional-resonant controller to generate an inverter control signal to regulate the input current, wherein a resonant frequency of the proportional-resonant controller is determined based on a frequency of the D-axis current component.

7. The motor control system according to claim 6, wherein, The operations further include: generating the inverter control signal by performing space vector pulse width modulation on an α-axis voltage component and a β-axis voltage component output by the proportional-resonant controller.

8. The motor control system according to claim 6, wherein, A transfer function of the proportional-resonant controller includes a cut-off frequency, and the cut-off frequency is determined according to the resonant frequency of the proportional-resonant controller.

9. The motor control system according to claim 6, wherein, The set value of the D-axis current component varies within a period corresponding to the frequency of the D-axis current component, and the set value of the Q-axis current component is zero.

10. The motor control system according to claim 6, wherein, The motor includes at least a permanent magnet synchronous motor, and the coordinate transformation includes at least a Clarke transformation.

11. A computer-readable storage medium storing computer instructions therein, characterized in that, When executed by the processor, the computer instructions cause the motor control method according to any one of claims 1 to 5 to be implemented.

12. A computer program product, the computer program product comprising a computer program, characterized in that, When executed by the processor, the computer program implements the motor control method according to any one of claims 1 to 5.

Images