Permanent magnet synchronous motor control method and device and storage medium

Abstract

The invention relates to the field of motor control, and discloses a permanent magnet synchronous motor control method and device and a storage medium, and the method comprises the steps: obtaining a bus voltage and a motor rotating speed, and according to the bus voltage, the motor rotating speed, an initial torque limit value, a torque request value, motor control related information and a flux linkage limit value and torque limit value corresponding table, obtaining a torque limit value; determining a torque target value; determining a target D-axis current according to the torque target value, the stator flux linkage limit value corresponding to the torque target value and a D-axis current correspondence table; determining a target Q-axis current according to the target D-axis current, the torque target value and a pre-stored parameter table, and controlling a target motor according to the target D-axis current and the target Q-axis current; wherein the pre-constructed D-axis current corresponding table comprises the corresponding relation among the torque, the stator flux linkage and the D-axis current, the effects of reducing tables and calibration data and saving storage space and calibration quantity are achieved, and the solving accuracy of the D-axis current and the Q-axis current is improved.

Description

Technical Field

[0001] The present invention relates to the field of motor control, and in particular to a permanent magnet synchronous motor control method, device and storage medium. Background Art

[0002] The current permanent magnet synchronous motor control scheme mostly uses a table lookup method to generate the D-axis and Q-axis currents, that is, a three-dimensional table of the D-axis current and the Q-axis current is looked up according to different torque request values, motor speeds and bus voltages. Moreover, the current instructions in the weak magnetic area and the non-weak magnetic area are all generated by table lookup. This scheme has the problem of huge current table data and occupies too much storage space.

[0003] Moreover, the above scheme cannot make the current command change with the change of motor parameters. For example, when the rotor flux decreases due to the increase in temperature, the actual torque will deviate. If you want to look up the table value to change with the rotor temperature, you need to increase the table dimension. The increase in table dimension will result in more storage resources being occupied and the calibration data of the table being larger.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a permanent magnet synchronous motor control method, device and storage medium, which achieves the effect of reducing tables and calibration data, saving storage space and calibration amount, and improving the accuracy of solving D-axis current and Q-axis current.

[0006] An embodiment of the present invention provides a permanent magnet synchronous motor control method, the method comprising:

[0007] Obtaining a bus voltage and a motor speed, and determining a torque target value according to the bus voltage, the motor speed, an initial torque limit value, a torque request value, motor control related information, and a pre-constructed corresponding table of flux limit value and torque limit value; wherein the motor control related information includes a stator resistance, a stator current amplitude, a stator electrical angular velocity, and a maximum modulation amplitude;

[0008] Determine a target D-axis current according to the torque target value, the stator flux limit value corresponding to the torque target value, and a pre-constructed D-axis current correspondence table;

[0009] Determine a target Q-axis current according to the target D-axis current, the torque target value, and a pre-stored parameter table, and control a target motor according to the target D-axis current and the target Q-axis current;

[0010] The pre-constructed D-axis current correspondence table includes the correspondence between torque, stator flux and D-axis current.

[0011] An embodiment of the present invention provides an electronic device, the electronic device comprising:

[0012] Processor and memory;

[0013] The processor is used to execute the steps of the permanent magnet synchronous motor control method described in any embodiment by calling the program or instruction stored in the memory.

[0014] An embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a program or instruction, wherein the program or instruction enables a computer to execute the steps of the permanent magnet synchronous motor control method described in any embodiment.

[0015] The embodiments of the present invention have the following technical effects:

[0016] By acquiring the bus voltage and the motor speed, the torque target value is determined according to the bus voltage, the motor speed, the initial torque limit value, the torque request value, the motor control related information and a pre-constructed flux limit and torque limit correspondence table. Then, the target D-axis current is determined according to the torque target value, the stator flux limit value corresponding to the torque target value and the pre-constructed D-axis current correspondence table. Then, the target Q-axis current is determined according to the target D-axis current, the torque target value and the pre-stored parameter table. According to the target D-axis current and the target Q-axis current, the target motor is controlled, thereby achieving the effect of reducing tables and calibration data, saving storage space and calibration amount, and improving the accuracy of solving the D-axis current and the Q-axis current. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 is a flow chart of a permanent magnet synchronous motor control method provided by an embodiment of the present invention;

[0019] Figure 2 is a schematic diagram of a torque request value limitation process provided by an embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of an area surrounded by an MTPA curve and an MTPV curve provided in an embodiment of the present invention;

[0021] Figure 4 is a schematic diagram of an initial correspondence table provided in an embodiment of the present invention;

[0022] Figure 5 is a schematic diagram of a D-axis current correspondence table provided in an embodiment of the present invention;

[0023] Figure 6 It is a schematic diagram of determining the corrected values ​​of the D-axis inductance lookup table value, the Q-axis inductance lookup table value, and the rotor flux lookup table value provided by an embodiment of the present invention;

[0024] Figure 7 is a schematic diagram of solving the target Q-axis current provided by an embodiment of the present invention;

[0025] Figure 8 is a flow chart of another permanent magnet synchronous motor control method provided by an embodiment of the present invention;

[0026] Fig. 9 It is a structural schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0028] The permanent magnet synchronous motor control method provided by the embodiment of the present invention is mainly applicable to the case where the D-axis current and the Q-axis current of the motor are calculated according to the torque request. The permanent magnet synchronous motor control method provided by the embodiment of the present invention can be executed by an electronic device.

[0029] Figure 1 is a flow chart of a permanent magnet synchronous motor control method provided by an embodiment of the present invention. Figure 1 , the permanent magnet synchronous motor control method specifically includes:

[0030] S110, obtaining the bus voltage and the motor speed, and determining the torque target value according to the bus voltage, the motor speed, the initial torque limit value, the torque request value, motor control related information, and a pre-constructed corresponding table of flux limit value and torque limit value.

[0031] Among them, the bus voltage is the voltage on the DC side of the inverter, which can be obtained by measurement. The motor speed refers to the number of rotations per minute of the motor, which can also be obtained by measurement. The initial torque limit value is a value used to calculate the subsequent stator flux limit value. It is 0 in the initial case and can be updated iteratively later. The torque request value is the torque value that the user needs the motor to output. The motor control related information is some parameter information that is fixed when the motor leaves the factory, including stator resistance, stator current amplitude, stator electrical angular velocity, and maximum modulation amplitude, where the maximum modulation amplitude can be 1. The pre-constructed flux limit and torque limit correspondence table includes the correspondence between the flux limit and the torque limit, which can be determined according to the pre-constructed D-axis current correspondence table. The pre-constructed D-axis current correspondence table includes the correspondence between torque, stator flux, and D-axis current. The torque target value is the torque value that the motor needs to output determined by calculation and analysis.

[0032] Specifically, the bus voltage and motor speed can be obtained by measuring, and further, the limit value for the torque request value can be calculated by combining the bus voltage, motor speed, initial torque limit value, motor control related information, and the corresponding table of flux limit value and torque limit value, and the torque request value is limited by the calculated limit value so that the torque request value is not greater than the calculated limit value. Then, the limited torque value is used as the new initial torque limit value to recalculate the limit value for the torque request value, and the torque request value is limited again. If the torque values ​​after two consecutive limits are the same, the same torque value after two consecutive limits is used as the torque target value; if the torque values ​​after two consecutive limits are different, the torque value after the last limit is used as the new initial torque limit value, and the next limit operation is performed until the torque values ​​after two consecutive limits are the same.

[0033] Based on the above example, the torque target value can be determined according to the bus voltage, motor speed, initial torque limit value, torque request value, motor control related information and the pre-built flux limit and torque limit correspondence table in the following way:

[0034] Determine the stator flux limit value based on bus voltage, motor speed, initial torque limit value and motor control related information;

[0035] Determine the maximum torque limit value according to the stator flux limit value and a pre-built correspondence table of flux limit value and torque limit value;

[0036] The minimum value between the maximum torque limit value and the torque request value is used as the process torque limit value;

[0037] In response to the process torque limit value being equal to the initial torque limit value, taking the process torque limit value as the torque target value;

[0038] In response to the process torque limit value not being equal to the initial torque limit value, the initial torque limit value is updated based on the process torque limit value, and the step of determining the stator flux limit value based on the bus voltage, the motor speed, the initial torque limit value and motor control related information is returned to be executed until the process torque limit value is equal to the initial torque limit value.

[0039] The stator flux limit is the limit value for the stator flux, that is, the maximum value of the stator flux in the current situation. The maximum torque limit is the limit value for the torque, that is, the maximum torque that can be output in the current situation. The process torque limit is the minimum value between the maximum torque limit and the torque request.

[0040] It can be understood that by searching for each different stator flux limit in the pre-constructed D-axis current correspondence table, multiple sets of torque and D-axis current correspondences corresponding to each stator flux limit can be determined, and the torque corresponding to the minimum value of the D-axis current in these multiple sets of torque and D-axis current correspondences is used as the maximum torque limit value corresponding to each stator flux limit, thereby constructing a flux limit and torque limit correspondence table.

[0041] Specifically, the stator flux limit can be calculated by combining the bus voltage, motor speed, initial torque limit value and motor control related information through the permanent magnet synchronous motor stator voltage equation and torque equation. The maximum torque limit corresponding to the stator flux limit can be determined through the flux limit and torque limit correspondence table. Furthermore, the maximum and minimum limits are performed, specifically, the minimum value of the maximum torque limit value and the torque request value is used as the process torque limit value to limit the torque request value, such as Figure 2 As shown. If the process torque limit value is equal to the initial torque limit value, it means that the torque limitation process tends to be stable, and the process torque limit value can be used as the torque target value. If the process torque limit value is not equal to the initial torque limit value, it means that the torque limitation process is not stable yet and feedback loop processing is still required. Therefore, the process torque limit value is used as the new initial torque limit value, and the step of determining the stator flux limit value again is returned until the process torque limit value is equal to the initial torque limit value, so that the torque limitation process is stable.

[0042] It is understandable that, normally, the initial torque limit value used when calculating the stator flux limit for the first time is 0. At this time, the stator flux limit is very large, resulting in a large maximum torque limit value. The torque request value is usually not limited. However, the initial torque limit value will be updated to the torque request value due to the return loop, and the stator flux limit will be recalculated to reduce the maximum torque limit value and limit it again. If it still cannot be limited, it means that the torque request value can be output. If it is limited, it needs to be fed back in the loop again to determine whether it will be further restricted.

[0043] Based on the above example, the motor control related information includes stator resistance, stator current amplitude, stator electrical angular velocity and maximum modulation amplitude. The stator flux limit can be determined according to the bus voltage, motor speed, initial torque limit value and motor control related information in the following way:

[0044] The stator flux limit is determined by the following formula:

[0045]

[0046] Among them, FluxSLim is the stator flux limit, Udc is the bus voltage, ModFac is the maximum modulation amplitude, the maximum modulation amplitude can be selected as 1, SpeedEm is the motor speed, TqLim is the initial torque limit value, R s is the stator resistance, I s is the stator current amplitude, Omege is the stator electrical angular velocity.

[0047] Based on the above example, the D-axis current correspondence table can be constructed in the following way:

[0048] Determine the maximum torque-to-current ratio curve according to the stator current amplitude and a pre-stored parameter table;

[0049] For each preset torque, according to the maximum torque-to-current ratio curve, multiple current combinations corresponding to the preset torque and stator flux linkage values ​​corresponding to each current combination are determined;

[0050] Determine a maximum torque-to-voltage ratio curve according to the minimum value of each stator flux linkage value corresponding to each preset torque and the current combination corresponding to the minimum value;

[0051] For each preset torque, according to the preset torque, the maximum torque-to-current ratio curve, the maximum torque-to-voltage ratio curve and the preset flux step, each preset flux under the preset torque is determined, and the preset D-axis current corresponding to each preset flux is determined;

[0052] A D-axis current correspondence table is constructed according to each preset torque, each preset flux linkage, and each preset D-axis current.

[0053] Among them, the stator current amplitude refers to the amplitude of the stator current sine wave in the permanent magnet synchronous motor. The pre-stored parameter table includes a D-axis inductance parameter table, a Q-axis inductance parameter table and a rotor flux parameter table. The D-axis inductance parameter table is the correspondence between the D-axis current, the Q-axis current and the D-axis inductance. The Q-axis inductance parameter table is the correspondence between the D-axis current, the Q-axis current and the Q-axis inductance. The rotor flux parameter table is the correspondence between the D-axis current, the Q-axis current and the rotor flux. The maximum torque current ratio curve (Maximum Torque Per Ampere, MTPA) is a set of operating points for the permanent magnet synchronous motor (PMSM) to obtain the maximum torque output with the minimum stator current under given load conditions. The preset torque is the individual torques interpolated between 0 and the maximum torque value. The current combination is a combination of the D-axis current and the Q-axis current. The stator flux value is the value of the stator flux calculated by the D-axis current and the Q-axis current in each current combination. The maximum torque per voltage ratio curve (MTPV) refers to the curve of the current combination of the D-axis current and the Q-axis current corresponding to the maximum torque obtained at the maximum stator voltage limit at different speeds. The preset flux step is the pre-set flux step. The preset flux is the flux values ​​interpolated with the preset flux step between the maximum torque current ratio curve and the maximum torque voltage ratio curve. The preset D-axis current is the D-axis current corresponding to the preset torque and the preset flux.

[0054] Specifically, interpolation is performed from 0 to the stator current amplitude to obtain multiple stator currents, and the D-axis current and Q-axis current corresponding to each stator current are calculated respectively. Then, in combination with the pre-stored parameter table, the corresponding D-axis inductance, Q-axis inductance and rotor flux are obtained, and the corresponding torque value is calculated according to the permanent magnet synchronous motor torque formula, thereby obtaining the D-axis and Q-axis current combination corresponding to the maximum torque under each stator current, that is, the maximum torque current ratio curve. For each preset torque, the current combination corresponding to the preset torque is determined on the maximum torque current ratio curve. At this time, the D-axis current is the largest, and the D-axis current is gradually reduced. Under the condition of not exceeding the corresponding stator current amplitude, the Q-axis current is solved, and then multiple groups of current combinations can be obtained, and the stator flux value corresponding to each group of current combinations can also be calculated. The minimum value of each stator flux value corresponding to each preset torque and the current combination corresponding to the minimum value are determined, that is, the working point on the maximum torque voltage ratio curve, and the maximum torque voltage ratio curve can be obtained. For each preset torque, interpolation is performed according to the preset flux step length between the maximum torque current ratio curve and the maximum torque voltage ratio curve according to the preset torque, and each preset flux under the preset torque is obtained, and then, the preset D-axis current corresponding to each preset flux can be determined by interpolation. The corresponding relationship between each preset torque, each preset flux and each preset D-axis current is determined, and a D-axis current corresponding table is constructed according to the corresponding relationship.

[0055] Based on the above example, each preset torque can be determined in the following way:

[0056] The maximum torque value is determined according to the maximum torque-current ratio curve, and each preset torque is determined according to the maximum torque value and the preset torque step.

[0057] The maximum torque value is the maximum value of the torque values ​​corresponding to the maximum torque current ratio curve. The preset torque step is a pre-set step for collecting the preset torque, such as 1Nm.

[0058] Specifically, the maximum torque value that can be obtained on the maximum torque current ratio curve from 0 with a preset torque step length is used as a preset torque for each movement of the preset torque step length.

[0059] Based on the above example, multiple current combinations corresponding to the preset torque and the stator flux linkage value corresponding to each current combination can be determined according to the maximum torque-to-current ratio curve in the following manner:

[0060] According to the maximum torque-current ratio curve, determine the maximum D-axis current corresponding to the preset torque;

[0061] Determine, according to the maximum D-axis current and the preset current interval, each D-axis current to be processed and a Q-axis current to be processed corresponding to each D-axis current to be processed;

[0062] Constructing multiple groups of current combinations according to each to-be-processed D-axis current and the to-be-processed Q-axis current corresponding to each to-be-processed D-axis current;

[0063] For each current combination, the corresponding D-axis inductance and Q-axis inductance are determined according to the current combination, the corresponding D-axis flux is determined according to the D-axis current, D-axis inductance and rotor flux to be processed in the current combination, the corresponding Q-axis flux is determined according to the Q-axis current and Q-axis inductance to be processed in the current combination, and the stator flux value corresponding to the current combination is determined according to the D-axis flux and Q-axis flux.

[0064] Among them, the maximum D-axis current is the D-axis current corresponding to the set torque on the maximum torque-current ratio curve. The preset current interval is a preset current interval for interpolation. The D-axis current to be processed is each D-axis current interpolated between 0 and the maximum D-axis current based on the preset current interval. The Q-axis current to be processed is the Q-axis current calculated based on the torque formula and the D-axis current to be processed. The total current value corresponding to the D-axis current to be processed and the Q-axis current to be processed is less than or equal to the stator current amplitude. The D-axis inductance and the Q-axis inductance are inductance values ​​determined according to the D-axis inductance parameter table and the Q-axis inductance parameter table, respectively. The rotor flux is the flux formed by the magnetic flux generated by the rotor permanent magnet and the stator winding. The D-axis flux and the Q-axis flux are values ​​calculated according to the existing formula. The stator flux value is the sum of the squares of the corresponding D-axis flux and the Q-axis flux.

[0065] Specifically, on the maximum torque-current ratio curve, the D-axis current corresponding to the preset torque is determined, that is, the maximum D-axis current. Starting from the maximum D-axis current, it decreases at a preset current interval to obtain multiple D-axis currents to be processed, and for each D-axis current to be processed, the D-axis current to be processed is substituted into the torque formula to obtain the corresponding Q-axis current to be processed. The D-axis current to be processed and the Q-axis current to be processed that have a corresponding relationship are combined to obtain multiple groups of current combinations. For each group of current combinations, according to the current combination, the D-axis inductance parameter table is searched to obtain the corresponding D-axis inductance, and the Q-axis inductance parameter table is searched to obtain the corresponding Q-axis inductance. Substitute the D-axis current to be processed, the D-axis inductance and the rotor flux in the current combination into the formula FluxD=Ld×Id+FluxPm, where FluxD is the D-axis flux, Ld is the D-axis inductance, Id is the D-axis current to be processed, and FluxPm is the rotor flux, thereby obtaining the corresponding D-axis flux. Substitute the Q-axis current and Q-axis inductance to be processed in the current combination into the formula FluxQ=Lq×Iq, where FluxQ is the Q-axis flux, Lq is the Q-axis inductance, and Iq is the Q-axis current to be processed, thereby obtaining the corresponding Q-axis flux. Further, the sum of the squares of the D-axis flux and the Q-axis flux is taken as the stator flux value corresponding to the current combination.

[0066] Based on the above example, the preset flux linkages under the preset torque can be determined according to the preset torque, the maximum torque current ratio curve, the maximum torque voltage ratio curve and the preset flux linkage step length in the following manner:

[0067] For each preset torque, a first flux linkage is determined according to a preset torque and a maximum torque current ratio curve, and a second flux linkage is determined according to a preset torque and a maximum torque voltage ratio curve;

[0068] Between the first flux linkage and the second flux linkage, each preset flux linkage under the preset torque is determined according to the preset flux linkage step length.

[0069] The first flux linkage is a flux linkage value corresponding to the preset torque on the maximum torque-current ratio curve, and the second flux linkage is a flux linkage value corresponding to the preset torque on the maximum torque-voltage ratio curve.

[0070] Specifically, for each preset torque, a first magnetic flux corresponding to the preset torque is determined on the maximum torque current ratio curve, and a second magnetic flux corresponding to the preset torque is determined on the maximum torque voltage ratio curve. Then, between the first magnetic flux and the second magnetic flux, interpolation is performed according to the preset magnetic flux step size to obtain each preset magnetic flux under the preset torque.

[0071] Based on the above example, a D-axis current correspondence table may be constructed according to each preset torque, each preset flux linkage, and each preset D-axis current in the following manner:

[0072] Constructing an initial correspondence table according to each preset torque, each preset flux linkage and each preset D-axis current;

[0073] For each preset torque in the initial correspondence table, determine the maximum D-axis current and the minimum D-axis current according to the preset torque and the initial correspondence table;

[0074] According to the maximum D-axis current and the minimum D-axis current corresponding to each preset torque, the initial corresponding table is expanded to obtain a D-axis current corresponding table.

[0075] The initial correspondence table is a correspondence table composed of preset torques, preset flux linkages, and preset D-axis currents that have corresponding relationships. The maximum D-axis current is the D-axis current on the maximum torque-to-current ratio curve under the preset torque. The minimum D-axis current is the D-axis current on the maximum torque-to-voltage ratio curve under the preset torque.

[0076] Specifically, the preset torque, preset flux and preset D-axis current with corresponding relationship are combined to construct an initial corresponding table. For the area outside the maximum torque current ratio curve, the D-axis current of the preset torque on the maximum torque current ratio curve, that is, the maximum D-axis current, is directly used. For the area outside the maximum torque voltage ratio curve, the D-axis current of the preset torque on the maximum torque voltage ratio curve, that is, the minimum D-axis current, is directly used. Thus, the preset torque can be expanded outside the area between the maximum torque current ratio curve and the maximum torque voltage ratio curve, and the D-axis current corresponding to each preset flux is expanded to the maximum D-axis current or the minimum D-axis current corresponding to the preset torque, so as to expand the initial corresponding table, and obtain the D-axis current corresponding table after expansion.

[0077] It can be understood that, for the preset torque, in the area between the maximum torque current ratio curve and the maximum torque voltage ratio curve, the corresponding relationship of the initial corresponding table is adopted. Outside this area, if it is the preset magnetic flux close to one side of the maximum torque current ratio curve, the corresponding D-axis current is determined to be the D-axis current on the maximum torque current ratio curve, that is, the maximum D-axis current; if it is the preset magnetic flux close to one side of the maximum torque voltage ratio curve, the corresponding D-axis current is determined to be the D-axis current on the maximum torque voltage ratio curve, that is, the minimum D-axis current.

[0078] Exemplarily, to obtain the MTPA curve, the stator current amplitude Is is compensated from 0 with a fixed compensation (optional step size is 1A), so that the angle of Is on the DQ coordinate plane is increased from 90 degrees with a fixed step size (optional step size is 1 degree) to 180 degrees, the D-axis current is Is*cos(angle), the Q-axis current is Is*sin(angle), and according to the motor parameter table (D-axis inductance parameter table, Q-axis inductance parameter table and rotor flux parameter table), the corresponding D-axis inductance, Q-axis inductance and rotor flux are obtained for each current combination of D-axis current and Q-axis current, and the corresponding torque value is calculated according to the permanent magnet synchronous motor torque formula, and the current combination of D-axis and Q-axis corresponding to the maximum torque under each stator current amplitude Is is obtained, which is the MTPA curve. For the calculation of the D-axis current on the MTPV curve, since there are D-axis currents under different torques on the MTPA curve, the D-axis current combination on the weak magnetic region and the MTPV curve can be obtained based on the MTPA curve. For the same torque value, there will be multiple DQ-axis current combinations on the DQ-axis plane. The torque is set from 0 and with a certain step size (preset torque step size, optional 1Nm) to the maximum torque value that can be obtained on the MTPA curve. For each torque value, the D-axis current corresponding to the MTPA of the current torque is used as the starting point. The current step size is a fixed step size (preset current interval, optional step size is 1A), and the D-axis current is continuously reduced. According to the torque formula Tq=1.5*PolePair*Iq(Id*Ld+FluxPm), Tq is the torque value, polepair is the number of motor pole pairs, Iq is the Q-axis current, Id is the D-axis current, Ld is the D-axis inductance, and FluxPm is the rotor flux. The corresponding Q-axis current is calculated until Is is greater than the Is limit. In this way, all the D-axis and Q-axis current combinations under this torque are obtained, and the D-axis flux, Q-axis flux and stator flux under each combination are calculated according to all the D-axis and Q-axis current combinations, and the stator flux value under all current combinations under the same torque is obtained. Among them, the D-axis and Q-axis current combination corresponding to the minimum stator flux value is the working point on the MTPV curve. The area surrounded by the MTPA curve and the MTPV curve is obtained, such as Figure 3 As shown. Regarding the calculation of the D-axis current in the weak magnetic region, the weak magnetic region on the DQ axis plane is the entire region covered by the MTPA curve and the MTPV curve. The stator flux values ​​of all current combinations under each torque have been obtained. A fixed step size (preset flux step size) is set to perform linear interpolation from the second flux corresponding to the MTPV curve to the first flux corresponding to the MTPA curve corresponding to the current torque. The D-axis current of each torque and flux under the weak magnetic region is obtained in turn, as shown in Figure 4As shown, it is the initial correspondence table. According to the calculation of the D-axis current in the weak magnetic region, the D-axis current correspondence table under different torques and flux linkages has been obtained. The torque corresponding to the minimum value of the D-axis current corresponding to different stator flux linkages in this table is the maximum torque limit value that can be achieved under the current stator flux linkage. This maximum torque limit value is used to limit the calculation of the torque request value. It should also be noted that the D-axis current in the weak magnetic region does not cover the entire plane with torque and flux linkage as coordinate axes. In order to prevent invalid values ​​from being obtained by checking the D-axis current correspondence table, the D-axis current in the weak magnetic region that has been obtained needs to be expanded to the entire plane. The horizontal and vertical coordinates of the D-axis current correspondence table are the torque and flux linkage amplitudes. For areas outside the MTPV curve at the same torque, that is, areas with smaller D-axis currents, the D-axis current on the MTPV curve of the current torque is directly used. For areas outside the MTPA curve, that is, areas with D-axis currents greater than those on the MTPA curve, the D-axis current of the MTPA curve corresponding to the current torque is directly used. Thus, the D-axis current correspondence table on the entire plane is obtained, as shown in Figure 5 shown. Figure 4 and Figure 5 Torque is the torque value, and Stator Flux is the magnetic flux value.

[0079] S120 , determining a target D-axis current according to the torque target value, the stator flux limit value corresponding to the torque target value, and a pre-constructed D-axis current corresponding table.

[0080] The target D-axis current is the D-axis current corresponding to the determined torque target value and the stator flux limit value, and is subsequently used to input a PI regulator (Proportional Integral Controller) to control the D-axis current value of the permanent magnet synchronous motor.

[0081] Specifically, in a pre-constructed D-axis current corresponding table, a search is performed according to the torque target value and the stator flux limit value corresponding to the torque target value, and the D-axis current obtained by the search is the target D-axis current.

[0082] S130, determining a target Q-axis current according to a target D-axis current, a target torque value, and a pre-stored parameter table, and controlling a target motor according to the target D-axis current and the target Q-axis current.

[0083] The target Q-axis current is the corresponding Q-axis current obtained by solving the target D-axis current. The target motor is the permanent magnet synchronous motor for which the control is to be solved.

[0084] Specifically, the target Q-axis current corresponding to the target torque value and the target D-axis current is obtained by combining the pre-stored parameter table and the permanent magnet synchronous motor torque formula, and the target Q-axis current and the target D-axis current are required to meet the stator current amplitude requirements. Then, the target D-axis current and the target Q-axis current can be used to control the target motor through the PI regulator.

[0085] Based on the above example, the parameter table includes a D-axis inductance parameter table, a Q-axis inductance parameter table, and a rotor flux parameter table. Then, the target Q-axis current can be determined according to the target D-axis current, the torque target value, and the pre-stored parameter table in the following manner:

[0086] Determine the Q-axis current to be corrected according to the target D-axis current, the torque target value, the D-axis inductance parameter table, the Q-axis inductance parameter table and the rotor flux parameter table;

[0087] Determine the Q-axis current limit value according to the target D-axis current and the stator current amplitude;

[0088] The minimum value between the Q-axis current to be corrected and the Q-axis current limit is used as the target Q-axis current.

[0089] The Q-axis current to be corrected is the Q-axis current corresponding to the target D-axis current determined by cyclic adjustment. The Q-axis current limit is the maximum Q-axis current that can be output under the limitation of the target D-axis current and the stator current amplitude.

[0090] Specifically, use the D-axis inductance parameter table, Q-axis inductance parameter table, rotor flux parameter table, and permanent magnet synchronous motor torque formula, substitute the target D-axis current and torque target value to solve, and obtain the Q-axis current to be corrected. According to the formula Solve for the Q-axis current limit, where I qLim is the Q-axis current limit, I s is the stator current amplitude, I d The minimum value between the Q-axis current to be corrected and the Q-axis current limit is taken as the target Q-axis current.

[0091] Exemplarily, the calculation of the Q-axis current to be corrected is based on the target D-axis current and the torque target value, and is calculated according to the permanent magnet synchronous motor torque formula IqRef = Tq / {1.5*Polepair*[Idref*(Ld-Lq)+FluxPm]}, where IqRef is the Q-axis current to be corrected, Tq is the matrix target value, PolePair is the number of motor pole pairs, Idref is the target D-axis current, Ld is the D-axis inductance lookup table value, Lq is the Q-axis inductance lookup table value, and FluxPm is the value corrected by the rotor flux lookup table value. The input of this formula is the value obtained by using the target D-axis current and the target Q-axis current to look up the D-axis inductance parameter table, the Q-axis inductance parameter table, and the rotor flux parameter table, that is, the corrected values ​​of the D-axis inductance lookup table value, the Q-axis inductance lookup table value, and the rotor flux lookup table value. The D-axis inductance parameter table, Q-axis inductance parameter table and rotor flux parameter table are obtained through simulation input or motor parameter identification. The rotor flux table value is corrected using the motor rotor temperature or stator temperature, rotor reference temperature and magnetic steel temperature coefficient, such as Figure 6 To prevent the calculated target Q-axis current from being too large, causing the total current to exceed the stator current limit, the calculated Q-axis current to be corrected needs to be output limited. Because the target D-axis current is calculated first, and the target D-axis current is a weak magnetic current, the D-axis current should be guaranteed first. Then, combined with the stator current limit, the Q-axis current limit is obtained, and the Q-axis current limit is used to limit the calculated Q-axis current to be corrected, and the target Q-axis current is obtained, as shown in the figure. Figure 7 shown.

[0092] Understandably, Figure 8 This is a flow chart of another permanent magnet synchronous motor control method. After obtaining the target D-axis current and the target Q-axis current, they are sent to the D-axis and Q-axis current regulators respectively, and closed-loop PI adjustment is performed according to the actual D-axis feedback current and Q-axis feedback current, and the D-axis voltage command and the Q-axis voltage command are output.

[0093] The present invention has the following technical effects: by acquiring the bus voltage and the motor speed, the torque target value is determined according to the bus voltage, the motor speed, the initial torque limit value, the torque request value, the motor control related information and a pre-constructed flux limit and torque limit correspondence table, and then, according to the torque target value, the stator flux limit value corresponding to the torque target value and the pre-constructed D-axis current correspondence table, the target D-axis current is determined, and then according to the target D-axis current, the torque target value and the pre-stored parameter table, the target Q-axis current is determined, and according to the target D-axis current and the target Q-axis current, the target motor is controlled, thereby achieving the effect of reducing tables and calibration data, saving storage space and calibration amount, and improving the accuracy of solving the D-axis current and the Q-axis current.

[0094] Fig. 9Schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. Fig. 9 As shown, the electronic device 400 includes one or more processors 401 and a memory 402 .

[0095] The processor 401 may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device 400 to perform desired functions.

[0096] The memory 402 may include one or more computer program products, and the computer program product may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 401 may run the program instructions to implement the permanent magnet synchronous motor control method of any embodiment of the present invention described above and / or other desired functions. Various contents such as initial external parameters, thresholds, etc. may also be stored in the computer-readable storage medium.

[0097] In one example, the electronic device 400 may further include: an input device 403 and an output device 404, which are interconnected via a bus system and / or other forms of connection mechanisms (not shown). The input device 403 may include, for example, a keyboard, a mouse, etc. The output device 404 may output various information to the outside, including early warning information, braking force, etc. The output device 404 may include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto, etc.

[0098] Of course, to simplify, Fig. 9 Only some of the components related to the present invention in the electronic device 400 are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, according to specific application conditions, the electronic device 400 may also include any other appropriate components.

[0099] In addition to the above methods and devices, an embodiment of the present invention may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of the permanent magnet synchronous motor control method provided by any embodiment of the present invention.

[0100] The computer program product may be written in any combination of one or more programming languages ​​to write program code for performing the operations of the embodiments of the present invention, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0101] In addition, an embodiment of the present invention may also be a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, enables the processor to execute the steps of the permanent magnet synchronous motor control method provided by any embodiment of the present invention.

[0102] The computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0103] It should be noted that the terms used in the present invention are only for describing specific embodiments, rather than limiting the scope of the present application. As shown in the present specification, unless the context clearly indicates an exception, the words "one", "a", "a kind of" and / or "the" do not specifically refer to the singular, but may also include the plural. The terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method or device 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 or device. In the absence of further restrictions, the elements defined by the sentence "include one..." do not exclude the presence of other identical elements in the process, method or device including the elements.

[0104] It should also be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A permanent magnet synchronous motor control method, characterized in that: include: Obtaining a bus voltage and a motor speed, and determining a torque target value according to the bus voltage, the motor speed, an initial torque limit value, a torque request value, motor control related information, and a pre-constructed corresponding table of flux limit value and torque limit value; wherein the motor control related information includes a stator resistance, a stator current amplitude, a stator electrical angular velocity, and a maximum modulation amplitude; Determine a target D-axis current according to the torque target value, the stator flux limit value corresponding to the torque target value, and a pre-constructed D-axis current correspondence table; Determine a target Q-axis current according to the target D-axis current, the torque target value, and a pre-stored parameter table, and control a target motor according to the target D-axis current and the target Q-axis current; The pre-constructed D-axis current correspondence table includes the correspondence between torque, stator flux and D-axis current.

2. The method according to claim 1, characterized in that The step of determining the torque target value according to the bus voltage, the motor speed, the initial torque limit value, the torque request value, motor control related information, and a pre-constructed corresponding table of flux limit value and torque limit value includes: Determining a stator flux limit value according to the bus voltage, the motor speed, the initial torque limit value and motor control related information; Determining a maximum torque limit value according to the stator flux limit value and a pre-constructed flux limit value and torque limit value correspondence table; Using the minimum value between the maximum torque limit value and the torque request value as the process torque limit value; In response to the process torque limit value being equal to the initial torque limit value, taking the process torque limit value as a torque target value; In response to the process torque limit value not being equal to the initial torque limit value, the initial torque limit value is updated based on the process torque limit value, and the step of determining the stator flux limit value based on the bus voltage, the motor speed, the initial torque limit value and motor control related information is returned to be executed until the process torque limit value is equal to the initial torque limit value.

3. The method according to claim 2, characterized in that The determining of the stator flux limit value according to the bus voltage, the motor speed, the initial torque limit value and motor control related information includes: The stator flux limit is determined by the following formula: Wherein, FluxSLim is the stator flux limit, Udc is the bus voltage, ModFac is the maximum modulation amplitude, SpeedEm is the motor speed, TqLim is the initial torque limit, R s is the stator resistance, I s is the stator current amplitude, and Omega is the stator electrical angular velocity.

4. The method according to claim 1, characterized in that: The D-axis current correspondence table is constructed based on the following method: Determine the maximum torque-to-current ratio curve according to the stator current amplitude and a pre-stored parameter table; For each preset torque, according to the maximum torque-to-current ratio curve, determining a plurality of current combinations corresponding to the preset torque and a stator flux linkage value corresponding to each current combination; Determine a maximum torque-to-voltage ratio curve according to a minimum value among the stator flux linkage values ​​corresponding to the preset torques and a current combination corresponding to the minimum value; For each preset torque, according to the preset torque, the maximum torque-to-current ratio curve, the maximum torque-to-voltage ratio curve and the preset flux step, each preset flux under the preset torque is determined, and a preset D-axis current corresponding to each preset flux is determined; A D-axis current correspondence table is constructed according to each preset torque, each preset flux linkage, and each preset D-axis current.

5. The method according to claim 4, characterized in that Determining, according to the maximum torque-to-current ratio curve, a plurality of current combinations corresponding to the preset torque and a stator flux linkage value corresponding to each current combination, comprises: Determining the maximum D-axis current corresponding to the preset torque according to the maximum torque-to-current ratio curve; According to the maximum D-axis current and the preset current interval, determining each D-axis current to be processed and the Q-axis current to be processed corresponding to each D-axis current to be processed; wherein the total current value corresponding to the D-axis current to be processed and the Q-axis current to be processed is less than or equal to the stator current amplitude; Constructing multiple groups of current combinations according to each to-be-processed D-axis current and the to-be-processed Q-axis current corresponding to each to-be-processed D-axis current; For each current combination, the corresponding D-axis inductance and Q-axis inductance are determined according to the current combination, the corresponding D-axis flux is determined according to the D-axis current to be processed in the current combination, the D-axis inductance and the rotor flux, the corresponding Q-axis flux is determined according to the Q-axis current to be processed in the current combination and the Q-axis inductance, and the stator flux value corresponding to the current combination is determined according to the D-axis flux and the Q-axis flux.

6. The method according to claim 4, characterized in that Determining each preset flux under the preset torque according to the preset torque, the maximum torque current ratio curve, the maximum torque voltage ratio curve and the preset flux step length includes: For each preset torque, determining a first flux linkage according to the preset torque and the maximum torque-to-current ratio curve, and determining a second flux linkage according to the preset torque and the maximum torque-to-voltage ratio curve; Between the first flux linkage and the second flux linkage, each preset flux linkage under the preset torque is determined according to a preset flux linkage step.

7. The method according to claim 4, characterized in that The D-axis current correspondence table is constructed according to each preset torque, each preset flux linkage and each preset D-axis current, including: Constructing an initial correspondence table according to each preset torque, each preset flux linkage and each preset D-axis current; For each preset torque in the initial correspondence table, determining a maximum D-axis current and a minimum D-axis current according to the preset torque and the initial correspondence table; According to the maximum D-axis current and the minimum D-axis current corresponding to each preset torque, the initial correspondence table is expanded to obtain a D-axis current correspondence table.

8. The method according to claim 1, characterized in that The parameter table includes a D-axis inductance parameter table, a Q-axis inductance parameter table and a rotor flux parameter table; the target Q-axis current is determined according to the target D-axis current, the torque target value and the pre-stored parameter table, including: Determining the Q-axis current to be corrected according to the target D-axis current, the torque target value, the D-axis inductance parameter table, the Q-axis inductance parameter table, and the rotor flux parameter table; Determining a Q-axis current limit value according to the target D-axis current and the stator current amplitude; The minimum value between the to-be-corrected Q-axis current and the Q-axis current limit is used as the target Q-axis current.

9. An electronic device, characterized in that: The electronic device comprises: Processor and memory; The processor is used to execute the steps of the permanent magnet synchronous motor control method according to any one of claims 1 to 8 by calling the program or instruction stored in the memory.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a program or instruction, and the program or instruction enables a computer to execute the steps of the permanent magnet synchronous motor control method according to any one of claims 1 to 8.

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