A method for suppressing torque pulsation of a permanent magnet synchronous motor and a related system

Abstract

The present application discloses a method for suppressing torque pulsation of a permanent magnet synchronous motor and a related system, which relates to the field of vehicle technology, and can reduce the torque pulsation of the permanent magnet synchronous motor in a simple manner, and can avoid the use of a high-performance low-pass filter, and avoid causing contradictions in the accuracy and stability of the system. The method for suppressing torque pulsation of a permanent magnet synchronous motor includes: obtaining the quadrature axis current and the direct axis current of the current loop of the permanent magnet synchronous motor control system; performing compensation operations on the quadrature axis current and the direct axis current to obtain a quadrature axis current reference DC quantity and a direct axis current reference DC quantity respectively; and inputting the quadrature axis current reference DC quantity and the direct axis current reference DC quantity into the current loop to perform closed-loop control of the current.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a method for suppressing torque pulsation of a permanent magnet synchronous motor and a related system. Background Art

[0002] At present, the technology of new energy vehicles is developing more and more rapidly. Driving permanent magnet synchronous motors is the core component of new energy vehicles. Among them, permanent magnet synchronous motors have the advantages of high efficiency, high output torque, high power density and good dynamic performance, and gradually become the first choice for pure electric vehicle drive systems. The torque pulsation of permanent magnet synchronous motors is closely related to the harmonic components of motor phase currents. Therefore, specific harmonic components in motor phase currents can be controlled to eliminate torque pulsation by suppressing specific harmonic currents or injecting specific harmonic currents to generate counter torque, thereby suppressing or eliminating torque pulsation. The existing harmonic control methods of permanent magnet synchronous motors are mainly multi-synchronous rotating coordinate system control methods.

[0003] However, the traditional multi-synchronous rotating coordinate system control method requires a large number of coordinate transformations and the design of high-performance low-pass filters, and there is a contradiction between the accuracy and stability of the system. Summary of the invention

[0004] The embodiments of the present application provide a method for suppressing torque pulsation of a permanent magnet synchronous motor and a related system, which can reduce the torque pulsation of the permanent magnet synchronous motor in a simple manner, avoid the use of a high-performance low-pass filter, and avoid causing conflicts in the accuracy and stability of the system.

[0005] According to a first aspect of an embodiment of the present application, a method for suppressing torque pulsation of a permanent magnet synchronous motor is provided, comprising:

[0006] Obtain the quadrature-axis current and direct-axis current of the current loop of the permanent magnet synchronous motor control system;

[0007] Performing compensation operation on the quadrature-axis current and the direct-axis current to obtain a quadrature-axis current reference DC value and a direct-axis current reference DC value respectively;

[0008] The quadrature-axis current reference DC value and the direct-axis current reference DC value are input into the current loop to perform closed-loop control of the current.

[0009] In some implementations, performing compensation operation on the quadrature-axis current and the direct-axis current to obtain a quadrature-axis current reference DC value and a direct-axis current reference DC value, respectively, includes:

[0010] Based on the direct-axis current, a direct-axis current DC value is obtained;

[0011] Acquire a power factor angle of the permanent magnet synchronous motor, and obtain a direct-axis reference current based on the power factor angle, the quadrature-axis current, and the direct-axis current;

[0012] The direct-axis current reference DC value is obtained based on the direct-axis current DC value and the direct-axis reference current.

[0013] In some implementations, the acquiring the power factor angle of the permanent magnet synchronous motor, and obtaining the direct-axis reference current based on the power factor angle, the quadrature-axis current, and the direct-axis current, comprises:

[0014] Obtaining the power factor angle of the permanent magnet synchronous motor;

[0015] The square of the quadrature-axis current and the square of the direct-axis current are summed and the square root is calculated, and the value obtained by the square root is multiplied by the cosine value of the power factor angle to obtain a direct-axis reference current;

[0016] The obtaining the direct-axis current reference direct-axis current based on the direct-axis current direct-axis current and the direct-axis reference current includes:

[0017] The direct-axis reference current and the direct-axis current DC value are subjected to a difference operation and then summed with the direct-axis current DC value to obtain the direct-axis current reference DC value.

[0018] In some implementations, performing compensation operation on the quadrature-axis current and the direct-axis current to obtain a quadrature-axis current reference DC value and a direct-axis current reference DC value, respectively, includes:

[0019] Based on the quadrature-axis current, obtaining a DC value of the quadrature-axis current;

[0020] Obtaining a quadrature-axis harmonic current based on the quadrature-axis current and the quadrature-axis current DC value;

[0021] Based on the quadrature-axis harmonic current and the direct-axis current DC amount, a predicted pulsating torque is obtained;

[0022] Performing equivalent harmonic calculation on the predicted pulsating torque to obtain a reference harmonic current;

[0023] The quadrature-axis current reference DC value is obtained based on the quadrature-axis harmonic current and the reference harmonic current.

[0024] In some implementations, obtaining the quadrature-axis harmonic current based on the quadrature-axis current and the quadrature-axis current DC value includes:

[0025] Performing a difference operation on the quadrature-axis current and the quadrature-axis current DC value to obtain the quadrature-axis harmonic current;

[0026] The obtaining the quadrature-axis current reference DC value based on the quadrature-axis harmonic current and the reference harmonic current comprises:

[0027] Performing a difference operation on the quadrature-axis harmonic current and the reference harmonic current to obtain a quadrature-axis equivalent harmonic current;

[0028] The quadrature-axis current DC value and the quadrature-axis equivalent harmonic current are summed to obtain the quadrature-axis current reference DC value.

[0029] According to a second aspect of an embodiment of the present application, a permanent magnet synchronous motor torque pulsation suppression system is provided, comprising:

[0030] A current acquisition module, used to acquire the quadrature-axis current and direct-axis current of the current loop of the permanent magnet synchronous motor control system;

[0031] An operation module, used for performing compensation operation on the quadrature-axis current and the direct-axis current to obtain a quadrature-axis current reference DC value and a direct-axis current reference DC value respectively;

[0032] The current output module is used to input the quadrature-axis current reference DC quantity and the direct-axis current reference DC quantity into the current loop to perform closed-loop control of the current.

[0033] In some embodiments, the computing module includes:

[0034] A direct-axis current average value module, used for obtaining a direct-axis current DC value based on the direct-axis current;

[0035] A power factor lookup table module is used to obtain the power factor angle of the permanent magnet synchronous motor;

[0036] The direct-axis reference current calculation module is used to sum the square of the quadrature-axis current and the square of the direct-axis current and then take the square root, and multiply the square root value by the cosine value of the power factor angle to obtain the direct-axis reference current.

[0037] In some implementations, the computing module further includes:

[0038] A quadrature-axis current average value module, used for obtaining a quadrature-axis current DC value based on the quadrature-axis current;

[0039] A pulsating torque prediction module, used for obtaining a predicted pulsating torque based on the direct-axis current DC amount;

[0040] The equivalent harmonic current calculation module is used to perform equivalent harmonic calculation on the predicted pulsating torque to obtain a reference harmonic current.

[0041] In some implementations, the computing module further includes:

[0042] At least two operators are used to perform difference operation or sum operation.

[0043] According to a third aspect of the embodiments of the present application, a permanent magnet synchronous motor control system is provided, comprising:

[0044] A permanent magnet synchronous motor torque pulsation suppression system as described in the second aspect.

[0045] The method and related system for suppressing torque pulsation of a permanent magnet synchronous motor provided in the embodiment of the present application obtains the quadrature-axis current and the direct-axis current from the current loop, and inputs the quadrature-axis current reference DC quantity and the direct-axis current reference DC quantity after current compensation operation into the current loop. The quadrature-axis current reference DC quantity and the direct-axis current reference DC quantity can be closed-loop controlled in the current loop, and the torque pulsation of the permanent magnet synchronous motor is suppressed by current compensation. The suppression accuracy is high, the stability is good, and the method is simple. The use of a high-performance low-pass filter can be avoided, and the contradiction between the accuracy and stability of the system can be avoided. The method for suppressing torque pulsation of a permanent magnet synchronous motor provided in the embodiment of the present application is simple, reliable, and easy to implement. There is no need to make significant modifications to the motor control algorithm, and it can be reused for different motor controllers. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic flow chart of a method for suppressing torque pulsation of a permanent magnet synchronous motor provided in an embodiment of the present application;

[0047] Figure 2 A schematic structural block diagram of a permanent magnet synchronous motor torque pulsation suppression system provided in an embodiment of the present application;

[0048] Figure 3 A schematic structural block diagram of a computing module provided in an embodiment of the present application;

[0049] Figure 4 A schematic structural block diagram of a permanent magnet synchronous motor control system provided in an embodiment of the present application;

[0050] Figure 5 A schematic structural block diagram of another permanent magnet synchronous motor control system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to better understand the technical solutions provided by the embodiments of this specification, the technical solutions of the embodiments of this specification are described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of this specification and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of this specification, rather than limitations on the technical solutions of this specification. In the absence of conflict, the embodiments of this specification and the technical features in the embodiments can be combined with each other.

[0052] In this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements limited by the statement "comprise one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. The term "more than two" includes two or more than two situations.

[0053] At present, the technology of new energy vehicles is developing more and more rapidly. Driving permanent magnet synchronous motors is the core component of new energy vehicles. Among them, permanent magnet synchronous motors have the advantages of high efficiency, high output torque, high power density and good dynamic performance, and gradually become the first choice for pure electric vehicle drive systems. The torque pulsation of permanent magnet synchronous motors is closely related to the harmonic components of motor phase currents. Therefore, specific harmonic components in motor phase currents can be controlled to suppress specific harmonic currents to eliminate torque pulsation or inject specific harmonic currents to generate counter torque, thereby achieving torque pulsation suppression or elimination. Existing harmonic control methods for permanent magnet synchronous motors mainly include multi-synchronous rotating coordinate system control and resonance control.

[0054] However, the traditional synchronous rotating coordinate system control method requires a large number of coordinate transformations and the design of high-performance low-pass filters, which makes the system contradictory in terms of accuracy and stability, and leads to large signal delays and poor real-time performance. The ideal resonant controller has characteristic distortion after discretization and digital realization, and it is difficult to ensure stable control of high-frequency signals when the motor is running at high speed.

[0055] In view of this, an embodiment of the present application provides a method for suppressing torque pulsation of a permanent magnet synchronous motor and a related system, which can reduce the torque pulsation of the permanent magnet synchronous motor in a simple way, avoid the use of a high-performance low-pass filter, and avoid causing contradictions in the accuracy and stability of the system.

[0056] In a first aspect of an embodiment of the present application, a method for suppressing torque pulsation of a permanent magnet synchronous motor is provided. Figure 1 A schematic flow chart of a method for suppressing torque pulsation of a permanent magnet synchronous motor provided in an embodiment of the present application. Figure 1 As shown, the method for suppressing torque pulsation of a permanent magnet synchronous motor provided in an embodiment of the present application includes:

[0057] S100: Obtain the quadrature-axis current and direct-axis current of the current loop of the permanent magnet synchronous motor control system. The quadrature-axis current and direct-axis current can be transformed into coordinates, Clark transformed, Park transformed, etc. in the current loop.

[0058] S200: Compensation operation is performed on the quadrature axis current and the direct axis current to obtain a quadrature axis current reference DC value and a direct axis current reference DC value, respectively. The compensation operation is mainly current compensation, which can be mainly compensation for the DC component of the current. A series of separate compensation operations can be performed on the quadrature axis current and the direct axis current to obtain a quadrature axis current reference DC value and a direct axis current reference DC value, respectively.

[0059] S300: Input the cross-axis current reference DC quantity and the direct-axis current reference DC quantity into the current loop to perform closed-loop control of the current. Input the cross-axis current reference DC quantity and the direct-axis current reference DC quantity that have undergone current compensation calculation into the current loop. The cross-axis current reference DC quantity and the direct-axis current reference DC quantity can undergo coordinate system transformation, Clark transformation, Park transformation and other transformation processes within the current loop, thereby achieving closed-loop control of the current and suppressing the torque pulsation of the permanent magnet synchronous motor by current compensation. There is no need to set a high-performance low-pass filter, nor is there a need to perform a large number of coordinate transformations. There will be no contradiction between the accuracy and stability of the system, and there will be no problem of poor real-time performance due to signal delay.

[0060] The method for suppressing torque pulsation of a permanent magnet synchronous motor provided in the embodiment of the present application obtains the quadrature-axis current and the direct-axis current from the current loop, and inputs the quadrature-axis current reference DC quantity and the direct-axis current reference DC quantity after current compensation operation into the current loop. The quadrature-axis current reference DC quantity and the direct-axis current reference DC quantity can be closed-loop controlled in the current loop, and the torque pulsation of the permanent magnet synchronous motor is suppressed by current compensation. The suppression accuracy is high, the stability is good, and the method is simple. The use of a high-performance low-pass filter can be avoided, and the contradiction between the accuracy and stability of the system can be avoided. The method for suppressing torque pulsation of a permanent magnet synchronous motor provided in the embodiment of the present application is simple, reliable, and easy to implement. There is no need to make significant modifications to the motor control algorithm, and it can be reused for different motor controllers.

[0061] In some implementations, step S200 may include:

[0062] Based on the direct axis current, the direct axis current DC quantity is obtained. Exemplarily, the direct axis current id of the current loop is obtained through the coordinate transformation of the permanent magnet synchronous motor control system, and the direct axis DC quantity id0 corresponding to the fundamental wave component of the alternating and direct axis current is obtained through the current average module.

[0063] The power factor angle of the permanent magnet synchronous motor is obtained, and the direct axis reference current is obtained based on the power factor angle, the quadrature axis current and the direct axis current. The power factor angle can be obtained based on the phase voltage and the phase current, and the direct axis reference current can be obtained through calculation.

[0064] Exemplarily, the power factor angle of the permanent magnet synchronous motor is obtained, and the direct axis reference current is obtained based on the power factor angle, the quadrature axis current and the direct axis current, including:

[0065] Obtain the power factor angle of the permanent magnet synchronous motor. Collect the phase angle difference between the phase voltage and phase current of the permanent magnet synchronous motor and obtain the power factor angle through the power factor lookup module.

[0066] The square of the quadrature-axis current and the square of the direct-axis current are summed and then squared, and the square root is multiplied by the cosine value of the power factor angle to obtain the direct-axis reference current. The power factor angle and the phase current can be input into the direct-axis reference current calculation module to obtain the corresponding direct-axis reference current id_ref.

[0067] Exemplarily, the power factor lookup module is obtained through actual testing, and the phase voltage and phase current of the permanent magnet synchronous motor at the same time are collected through the phase voltage sensor and the phase current sensor, and the permanent magnet synchronous motor is controlled to operate under different working conditions to record the phase voltage, phase current, speed, and motor torque and other parameters. By obtaining the phase difference between the phase voltage and phase current at the same time, the power factor angle of the permanent magnet synchronous motor at the current time can be obtained. Obtain the power factor angle under different loads in the full speed range The direct-axis reference current calculation module obtains the direct-axis reference current id_ref through the phase current and power factor angle collected by the phase current sensor through the following formula.

[0068]

[0069] Among them, iq is the quadrature axis current.

[0070] Based on the direct-axis current DC value and the direct-axis reference current, a direct-axis current reference DC value is obtained.

[0071] Exemplarily, obtaining a direct-axis current reference direct-axis current based on the direct-axis current direct-axis current and the direct-axis reference current includes:

[0072] The direct-axis reference current and the direct-axis current DC amount are subjected to difference calculation, and then summed with the direct-axis current DC amount to obtain the direct-axis current reference DC amount. The direct-axis reference current id_ref and the direct-axis current DC amount id0 are subjected to difference calculation to obtain the direct-axis current compensation amount id_com, and the direct-axis current compensation amount id_com is summed with the direct-axis current DC amount id0 to obtain the direct-axis current reference DC amount id0_ref.

[0073] In some implementations, step S200 may further include:

[0074] Based on the quadrature axis current, the quadrature axis current DC quantity is obtained. The quadrature axis current iq of the current loop is obtained through the coordinate transformation of the permanent magnet synchronous motor control system, and the quadrature axis DC quantity iq0 corresponding to the fundamental wave component of the quadrature axis current is obtained through the current average module.

[0075] Exemplarily, the current average value module utilizes the characteristics of the current structure and obtains the DC quantity corresponding to the fundamental component by the average value principle. Since the three-phase current is transformed from three-phase to two-phase, the times will be 6n and 6n+6 respectively, and n is any natural number greater than 0. The id and iq currents are integrated for T / 6 (T is the fundamental period), and the non-zero component obtained is the DC quantity corresponding to the fundamental component, and the fundamental component iq0 of the cross-axis current and the fundamental component id0 of the direct-axis current can be obtained. It should be noted that id0 and iq0 can be obtained synchronously, and the embodiments of the present application are not specifically limited.

[0076] Based on the quadrature-axis current and the quadrature-axis current DC value, the quadrature-axis harmonic current is obtained.

[0077] Based on the quadrature axis current and the DC value of the quadrature axis current, the quadrature axis harmonic current is obtained, which may include:

[0078] The quadrature axis current and the quadrature axis current DC quantity are subjected to a difference operation to obtain the quadrature axis harmonic current. For example, the quadrature axis harmonic current iq6h can be obtained by performing a difference operation on the initial quadrature axis current iq and the quadrature axis current DC quantity iq0.

[0079] The predicted pulsating torque is obtained based on the quadrature-axis harmonic current and the direct-axis current DC quantity.

[0080] Exemplarily, the pulsating torque prediction module can be used to obtain the predicted pulsating torque Te by inputting the quadrature-axis harmonic current iq6h and the direct-axis current DC quantity id0.

[0081] The equivalent harmonic calculation is performed on the predicted pulsating torque to obtain the reference harmonic current.

[0082] Exemplarily, the quadrature-axis harmonic current iq6h within a rotor angle is collected, and the average value of the quadrature-axis harmonic current iq6h is calculated to obtain the average value of the harmonic current within a rotor angle. The average value of the harmonic current can be used as a reference harmonic current iq6h_ref, and the predicted pulsating torque Te is obtained by the following formula:

[0083]

[0084] Among them, ΔL=Ld-Lq, Ld is the direct axis inductance, Lq is the quadrature axis inductance, is the magnetic flux corresponding to the direct axis.

[0085] Specifically, the reference harmonic current iq6h_ref corresponding to the quadrature-axis harmonic current can be obtained through the above equation for obtaining the predicted pulsating torque Te and the following equation for obtaining the predicted pulsating torque Te:

[0086]

[0087] Where Np is the number of permanent magnet synchronous motor pole pairs, By combining the two equations, the reference harmonic current iq6h_ref can be obtained.

[0088] Based on the quadrature-axis harmonic current and the reference harmonic current, a quadrature-axis current reference DC value is obtained.

[0089] Based on the quadrature-axis harmonic current and the reference harmonic current, the quadrature-axis current reference DC value is obtained, including:

[0090] Performing a difference operation on the quadrature-axis harmonic current and the reference harmonic current to obtain the quadrature-axis equivalent harmonic current;

[0091] The DC value of the quadrature-axis current and the quadrature-axis equivalent harmonic current are summed to obtain the DC value of the quadrature-axis current.

[0092] Specifically, the quadrature-axis harmonic current iq6h is differentially calculated with the reference harmonic current iq6h_ref to obtain the corresponding quadrature-axis equivalent harmonic current Δiq_ref, and the quadrature-axis equivalent harmonic current Δiq_ref is summed with the quadrature-axis current DC value iq0 to obtain the quadrature-axis current DC value iq0_ref.

[0093] A second aspect of the embodiments of the present application provides a permanent magnet synchronous motor torque pulsation suppression system. Figure 2 A schematic structural block diagram of a permanent magnet synchronous motor torque pulsation suppression system provided in an embodiment of the present application.

[0094] like Figure 2 As shown, the permanent magnet synchronous motor torque pulsation suppression system provided in the embodiment of the present application includes:

[0095] The current acquisition module 400 is used to acquire the quadrature-axis current and the direct-axis current of the current loop of the permanent magnet synchronous motor control system.

[0096] The operation module 500 is used to perform compensation operation on the quadrature-axis current and the direct-axis current to obtain a quadrature-axis current reference DC value and a direct-axis current reference DC value respectively;

[0097] The current output module 600 is used to input the quadrature-axis current reference DC quantity and the direct-axis current reference DC quantity into the current loop to perform closed-loop control of the current.

[0098] The permanent magnet synchronous motor torque pulsation suppression system provided in the embodiment of the present application obtains the quadrature axis current and the direct axis current from the current loop, and inputs the quadrature axis current reference DC quantity and the direct axis current reference DC quantity after the current compensation operation into the current loop. The quadrature axis current reference DC quantity and the direct axis current reference DC quantity can be closed-loop controlled in the current loop, and the torque pulsation of the permanent magnet synchronous motor is suppressed by current compensation. The suppression accuracy is high, the stability is good, and the method is simple. The use of a high-performance low-pass filter can be avoided, and the contradiction between the accuracy and stability of the system can be avoided. The method for suppressing the torque pulsation of the permanent magnet synchronous motor provided in the embodiment of the present application is simple, reliable, and easy to implement. There is no need to make significant modifications to the motor control algorithm, and it can be reused for different motor controllers.

[0099] In some embodiments, Figure 3 This is a schematic structural block diagram of a computing module provided in an embodiment of the present application. Figure 3 As shown, the operation module 500 includes:

[0100] The direct axis current average value module 510 is used to obtain the direct axis current DC quantity based on the direct axis current. The direct axis current id passes through the direct axis current average value module 510 to obtain the direct axis DC quantity id0 corresponding to the fundamental wave component of the alternating and direct axis current.

[0101] The power factor lookup table module 520 is used to obtain the power factor angle of the permanent magnet synchronous motor. The power factor lookup table module 520 collects the phase voltage and phase current of the permanent magnet synchronous motor at the same time through the phase voltage sensor and the phase current sensor, and controls the permanent magnet synchronous motor to operate under different working conditions to record parameters such as phase voltage, phase current, speed, and motor torque. By obtaining the phase difference between the phase voltage and phase current at the same time, the power factor angle of the permanent magnet synchronous motor at the current time can be obtained.

[0102] The direct-axis reference current calculation module 530 is used to sum the square of the quadrature-axis current and the square of the direct-axis current and then take the square root, and multiply the square root value by the cosine value of the power factor angle to obtain the direct-axis reference current. The direct-axis reference current calculation module 530 obtains the direct-axis reference current id_ref through the following formula using the phase current and the power factor angle collected by the phase current sensor.

[0103]

[0104] The operator can be used to perform a difference operation on the direct-axis reference current and the direct-axis current DC value, and then sum the difference with the direct-axis current DC value to obtain the direct-axis current reference DC value. The operation module may include multiple operators, and the operators may be used to perform a difference operation or a summation operation. Figure 3The operator for obtaining the direct-axis current reference DC value may be a first operator 571 and a second operator 572. The first operator 571 performs a difference operation on the direct-axis reference current id_ref and the direct-axis current DC value id0 to obtain the direct-axis current compensation value id_com. The second operator 572 sums the direct-axis current compensation value id_com and the direct-axis current DC value id0 to obtain the direct-axis current reference DC value id0_ref.

[0105] In some embodiments, reference Figure 3 The operation module 500 may further include:

[0106] The quadrature axis current average value module 540 is used to obtain the quadrature axis current DC value based on the quadrature axis current. The quadrature axis current iq passes through the quadrature axis current average value module 540 to obtain the quadrature axis DC value iq0 corresponding to the fundamental wave component of the quadrature axis current.

[0107] The operator may further include a third operator 573, which obtains the quadrature-axis harmonic current iq6h by performing a difference operation on the initial quadrature-axis current iq and the quadrature-axis current DC value iq0.

[0108] The pulsating torque prediction module 550 is used to obtain the predicted pulsating torque based on the direct-axis current DC value. The pulsating torque prediction module can be used to obtain the predicted pulsating torque Te by inputting the quadrature-axis harmonic current iq6h and the direct-axis current DC value id0.

[0109] The equivalent harmonic current calculation module 560 is used to perform equivalent harmonic calculation on the predicted pulsating torque to obtain a reference harmonic current. Exemplarily, the quadrature-axis harmonic current iq6h within a rotor angle is collected, and the average value of the quadrature-axis harmonic current iq6h is calculated to obtain the average value of the harmonic current within a rotor angle. The average value of the harmonic current can be used as the reference harmonic current iq6h_ref, and the predicted pulsating torque Te is obtained by the following formula:

[0110]

[0111] Among them, ΔL=Ld-Lq, Ld is the direct axis inductance, Lq is the quadrature axis inductance, is the magnetic flux corresponding to the direct axis.

[0112] Specifically, the reference harmonic current iq6h_ref corresponding to the quadrature-axis harmonic current can be obtained through the above equation for obtaining the predicted pulsating torque Te and the following equation for obtaining the predicted pulsating torque Te:

[0113]

[0114] Where Np is the number of permanent magnet synchronous motor pole pairs, By combining the two equations, the reference harmonic current iq6h_ref can be obtained.

[0115] The fourth operator 574 performs a difference operation on the quadrature-axis harmonic current iq6h and the reference harmonic current iq6h_ref to obtain the corresponding quadrature-axis equivalent harmonic current Δiq_ref, and the fifth operator 575 performs a sum operation on the quadrature-axis equivalent harmonic current Δiq_ref and the quadrature-axis current DC value iq0 to obtain the quadrature-axis current DC value iq0_ref.

[0116] According to a third aspect of the embodiments of the present application, a permanent magnet synchronous motor control system is provided. Figure 4 A permanent magnet synchronous motor control system is provided in an embodiment of the present application. Figure 4 As shown, a schematic structural block diagram of a permanent magnet synchronous motor control system provided in an embodiment of the present application includes:

[0117] A permanent magnet synchronous motor torque pulsation suppression system 1000 as described in the second aspect.

[0118] For example, Figure 5 This is a schematic structural block diagram of another permanent magnet synchronous motor control system provided in an embodiment of the present application. Figure 5 As shown, the permanent magnet synchronous motor control system provided in the embodiment of the present application mainly includes a current loop PI regulator and a speed loop PI regulator. Figure 5The current loop PI regulator and the speed loop PI regulator are both marked with PI. The permanent magnet synchronous motor control system also includes an ammeter lookup module Isearch, a Park inverse transformation module Inv-Park, an SVPWM module SVPWM, an Inverter inverter module Inverter, a Clark transformation module Clark, a Park transformation module Park, a permanent magnet synchronous motor PMSM, an encoder Encoder and a permanent magnet synchronous motor torque pulsation suppression system 1000, etc. According to the torque request signal torque_ref and the permanent magnet synchronous motor speed signal Motor_mechSpeed, the original quadrature axis current Iq_ref and the original direct axis current sum Id_ref are obtained through the ammeter lookup module Isearch. Specifically, based on the torque request signal torque_ref and the permanent magnet synchronous motor speed signal Motor_mechSpeed, the original quadrature axis current Iq_ref and the original direct axis current sum Id_ref are obtained by searching in the two-dimensional table stored in the ammeter lookup module Isearch. The permanent magnet synchronous motor torque pulsation suppression system obtains the compensated quadrature axis current DC amount iq0_ref and the direct axis current DC amount id0_ref through the input quadrature axis current iq and the direct axis current id. The operator can be used to obtain the adjusted quadrature axis current iq* based on the original quadrature axis current Iq_ref and the quadrature axis current DC amount iq0_ref, and the operator can be used to obtain the adjusted direct axis current id* based on the original direct axis current Id_ref and the direct axis current DC amount id0_ref. The current loop PI regulator and the speed loop PI regulator convert the regulated quadrature current iq* and the regulated direct current id* into quadrature voltage uq and direct voltage ud respectively. The quadrature voltage uq and direct voltage ud are voltages in the rotating coordinate system. The quadrature voltage uq and direct voltage ud are then converted into uβ and uα in the stationary coordinate system by the Park inverse transformation module Inv-Park, and finally converted into the switching signal for controlling the inverter module Inverter by the SVPWM module SVPWM, which is used to control the inverter Inverter to output the alternating three-phase current (ia, ib and ic), thereby controlling the permanent magnet synchronous motor PMSM. The Clark transformation module Clark converts the three-phase current into iα and iβ, and converts them into id and iq by the Park transformation module Park to realize the closed-loop control of the current.

[0119] The permanent magnet synchronous motor control system provided by the embodiment of the present application mainly solves the problem that the existing technology requires a large number of coordinate transformations, which increases the excessive amount of calculation of the motor controller. At the same time, the system has a contradiction in accuracy and stability because the average value of the AC and DC axis current is used to obtain the AC and DC axis fundamental components to avoid the design of a high-performance low-pass filter. At the same time, it can also solve the problem of large signal delay and poor signal real-time performance caused by the use of a low-pass filter. In addition, the embodiment of the present application is simple, reliable, and easy to implement. It does not require a significant modification of the motor control algorithm and can be reused for different motor controllers.

[0120] Although the preferred embodiments of this specification have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of this specification.

[0121] Obviously, those skilled in the art can make various changes and modifications to this specification without departing from the spirit and scope of this specification. Thus, if these modifications and variations of this specification fall within the scope of the claims of this specification and their equivalents, this specification is also intended to include these modifications and variations.

Claims

1. A method for suppressing torque pulsation of a permanent magnet synchronous motor, characterized in that: include: Obtain the quadrature-axis current and direct-axis current of the current loop of the permanent magnet synchronous motor control system; Performing compensation operation on the quadrature-axis current and the direct-axis current to obtain a quadrature-axis current reference DC value and a direct-axis current reference DC value respectively; Inputting the quadrature-axis current reference DC value and the direct-axis current reference DC value into the current loop to perform closed-loop control of the current; The compensating operation is performed on the quadrature-axis current and the direct-axis current to obtain a quadrature-axis current reference DC value and a direct-axis current reference DC value, respectively, including: Based on the direct-axis current, a direct-axis current DC value is obtained; Acquire a power factor angle of the permanent magnet synchronous motor, and obtain a direct-axis reference current based on the power factor angle, the quadrature-axis current, and the direct-axis current; Based on the direct-axis current DC value and the direct-axis reference current, obtaining the direct-axis current reference DC value; The step of acquiring the power factor angle of the permanent magnet synchronous motor and obtaining the direct-axis reference current based on the power factor angle, the quadrature-axis current and the direct-axis current comprises: Obtaining the power factor angle of the permanent magnet synchronous motor; The square of the quadrature-axis current and the square of the direct-axis current are summed and the square root is calculated, and the value obtained by the square root is multiplied by the cosine value of the power factor angle to obtain a direct-axis reference current; The obtaining the direct-axis current reference direct-axis current based on the direct-axis current direct-axis current and the direct-axis reference current includes: The direct-axis reference current and the direct-axis current DC value are subjected to a difference operation and then summed with the direct-axis current DC value to obtain the direct-axis current reference DC value.

2. The method for suppressing torque pulsation of a permanent magnet synchronous motor according to claim 1, characterized in that: The compensating operation is performed on the quadrature-axis current and the direct-axis current to obtain a quadrature-axis current reference DC value and a direct-axis current reference DC value, respectively, including: Based on the quadrature-axis current, obtaining a DC value of the quadrature-axis current; Obtaining a quadrature-axis harmonic current based on the quadrature-axis current and the quadrature-axis current DC value; Based on the quadrature-axis harmonic current and the direct-axis current DC amount, a predicted pulsating torque is obtained; Performing equivalent harmonic calculation on the predicted pulsating torque to obtain a reference harmonic current; The quadrature-axis current reference DC value is obtained based on the quadrature-axis harmonic current and the reference harmonic current.

3. The method for suppressing torque pulsation of a permanent magnet synchronous motor according to claim 2, characterized in that: The obtaining of the quadrature-axis harmonic current based on the quadrature-axis current and the quadrature-axis current DC value comprises: Performing a difference operation on the quadrature-axis current and the quadrature-axis current DC value to obtain the quadrature-axis harmonic current; The obtaining the quadrature-axis current reference DC value based on the quadrature-axis harmonic current and the reference harmonic current comprises: Performing a difference operation on the quadrature-axis harmonic current and the reference harmonic current to obtain a quadrature-axis equivalent harmonic current; The quadrature-axis current DC value and the quadrature-axis equivalent harmonic current are summed to obtain the quadrature-axis current reference DC value.

4. A permanent magnet synchronous motor torque pulsation suppression system, characterized in that: include: A current acquisition module, used to acquire the quadrature-axis current and direct-axis current of the current loop of the permanent magnet synchronous motor control system; An operation module, used for performing compensation operation on the quadrature-axis current and the direct-axis current to obtain a quadrature-axis current reference DC value and a direct-axis current reference DC value respectively; A current output module, used for inputting the quadrature-axis current reference DC quantity and the direct-axis current reference DC quantity into the current loop to perform closed-loop control of the current; The operation module comprises: A direct-axis current average value module, used for obtaining a direct-axis current DC value based on the direct-axis current; A power factor lookup table module is used to obtain the power factor angle of the permanent magnet synchronous motor; The direct-axis reference current calculation module is used to sum the square of the quadrature-axis current and the square of the direct-axis current and then take the square root, and multiply the square root value by the cosine value of the power factor angle to obtain the direct-axis reference current.

5. The permanent magnet synchronous motor torque pulsation suppression system according to claim 4, characterized in that: The operation module also includes: A quadrature-axis current average value module, used for obtaining a quadrature-axis current DC value based on the quadrature-axis current; A pulsating torque prediction module, used for obtaining a predicted pulsating torque based on the direct-axis current DC amount; The equivalent harmonic current calculation module is used to perform equivalent harmonic calculation on the predicted pulsating torque to obtain a reference harmonic current.

6. The permanent magnet synchronous motor torque ripple suppression system according to claim 4 or 5, characterized in that: The operation module also includes: At least two operators are used to perform difference operation or sum operation.

7. A permanent magnet synchronous motor control system, characterized in that: include: A permanent magnet synchronous motor torque pulsation suppression system as claimed in claim 4 or 5.

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