Prediction current control method and system for permanent magnet synchronous motor

Abstract

The invention discloses a permanent magnet synchronous motor predictive current control method and system, and belongs to the technical field of permanent magnet synchronous motor control. When a torque instruction changes drastically in a medium-high speed range, output voltage saturation is extremely easy to occur in dead-beat predictive current control, so that q-axis current is difficult to excite to an instruction value by the saturated output voltage in a sampling period, and the dynamic performance of torque rise at the medium-high speed is seriously reduced. Therefore, under the condition, the rising speed of the q-axis current is increased through flux weakening operation, and then the operation of increasing the torque is carried out at the higher q-axis current rising speed. The optimal flux-weakening current is determined based on a q-axis current rise time prediction algorithm, so that the total time required by flux-weakening operation and torque rise operation is minimum, and the torque dynamic performance of dead-beat prediction current control under medium and high speeds can be effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of permanent magnet synchronous motor control, and more specifically, relates to a permanent magnet synchronous motor predictive current control method and system. Background Art

[0002] Surface mounted permanent magnet synchronous motor (SPMSM) is widely used in servo control systems due to its high torque density, high efficiency, good control performance, etc. In recent years, due to the pursuit of ultra-fast dynamic response performance, deadbeat predictive current control has received widespread attention and has been deeply studied.

[0003] If the bus voltage is sufficient, the deadbeat predictive current control can theoretically achieve two cycles of deadbeat response performance. However, when the torque command changes drastically in the medium and high speed range, the reference voltage command calculated by the deadbeat predictive current controller is very likely to exceed the bus voltage limit and cause the controller output to saturate, making it difficult for the q-axis current to be excited to its command value by the saturated output voltage within one cycle, which seriously reduces the dynamic performance of torque rise at medium and high speeds. Therefore, it is of great significance to study a method that can improve the torque dynamic performance at medium and high speeds based on the deadbeat predictive current control. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a permanent magnet synchronous motor predictive current control method and system, which aims to improve the torque dynamic performance of zero-beat predictive current control at medium and high speeds.

[0005] In order to achieve the above object, in a first aspect, the present invention provides a method for predictive current control of a permanent magnet synchronous motor, comprising:

[0006] In each cycle, judging and determining the control operation of the next cycle, and performing the corresponding control operation in the next cycle;

[0007] The method of judging and determining the control operation of the k+1th cycle in the kth cycle includes:

[0008] S1, sample the signal in the kth cycle and obtain the d-axis current i d (k), q-axis current i q (k), q-axis current command and speed ω(k); k is the index of the sampling period;

[0009] S2, based on i d (k), i q (k) and ω(k), using the extended state observer, predict the d-axis current in the k+1th cycle Q-axis current d-axis lumped disturbance and q-axis lumped disturbance;

[0010] S3, based on the d-axis and q-axis predicted currents and lumped disturbances of the k+1th cycle, predict the current increment limit circle; wherein the current increment limit circle is the d-axis and q-axis currents in the k+1th cycle after a sampling period T s The circular current area that can be reached in the k+2th cycle after voltage excitation;

[0011] S4. Judgment Is it within the current increment limit circle? If so, the control operation of the k+1th cycle is to reduce the absolute value of the d-axis current and go to S8; otherwise, compare and The size of Then the control operation of the k+1th cycle is to reduce the torque and go to S8; if Then go to S5;

[0012] S5. Under the first condition in the k+1th cycle, predict the d-axis current in the k+2th cycle judge Is it within the current limit circle? If so, go to S6; otherwise, the control operation of the k+1th cycle is to increase the torque, go to S8; wherein the first condition includes: keeping the q-axis current unchanged and weakening the magnetic field at the maximum rate under the limitation of the current increment limit circle;

[0013] S6, the d-axis current is maintained at Under the condition of Rise to Minimum time required

[0014] The d-axis current is kept at Under the condition of Rise to Minimum time required

[0015] S7, comparison and The size of Then the control operation of the k+1th cycle is field weakening, and go to S8; if Then the control operation of the k+1th cycle is to increase the torque, and go to S8;

[0016] S8. End the judgment of the kth cycle.

[0017] Further preferably, the center of the current increment limit circle in the dq axis current coordinate system is The expression for the radius r is;

[0018]

[0019] Among them, L s is the dq axis inductance; R s is the stator resistance; ψ is the rotor flux; is the lumped disturbance of the d-axis in the k+1th period; is the q-axis lumped disturbance of the k+1th period; u dc is the DC bus voltage.

[0020] More preferably, the above S4 further includes: when When the current increment limit circle is within the range, the d and q axis voltage instructions are calculated in the kth cycle. and used to control the inverter to perform an operation of reducing the absolute value of the d-axis current in the k+1th cycle;

[0021] in,

[0022] when When within the current increment limit circle,

[0023] when When it is not within the current increment limit circle,

[0024]

[0025] Among them, the d-axis current command of the kth cycle is The calculation expression is:

[0026]

[0027] is the maximum stator current amplitude.

[0028] More preferably, the above S4 further includes: when is not within the current increment limit circle, and When the d and q axis voltage instructions are calculated in the kth cycle and Used to control the inverter to perform a torque reduction operation in the k+1th cycle;

[0029] in,

[0030] The d-axis current command of the kth cycle Maintain the d-axis current command of the previous cycle.

[0031] More preferably, the above S5 further includes: when When not within the current limit circle, calculate the d and q axis voltage instructions in the kth cycle and Used to control the inverter to perform an operation of increasing torque in the k+1th cycle;

[0032] in,

[0033] The d-axis current command of the kth cycle Maintain the d-axis current command of the previous cycle.

[0034] More preferably, the above S7 further includes: when When the d and q axis voltage instructions are calculated in the kth cycle and Used to control the inverter to perform magnetic weakening operation in the k+1th cycle;

[0035] in,

[0036] The d-axis current command of the kth cycle The calculation expression is:

[0037]

[0038] More preferably, the above S7 further includes: when When calculating the d and q axis voltage instructions and Used to control the inverter to perform an operation of increasing torque in the k+1th cycle;

[0039] in,

[0040] The d-axis current command of the kth cycle Maintain the d-axis current command of the previous cycle.

[0041] More preferably, and All are predicted using the q-axis current rise time prediction formula;

[0042] The current rise time prediction formula is used to predict the time at which the q-axis current changes from the initial value i when the d-axis current remains unchanged. q0 Rise to the final value i q1 Minimum time required Its expression is:

[0043]

[0044] in, L s is the dq axis inductance; R s is the stator resistance; ψ is the rotor flux;

[0045] Will and Substitute the expression In, get

[0046] Will and Substitute the expression In, get

[0047] Further preferably, the d-axis current of the k+1th cycle predicted by the extended state observer in S2 is Q-axis current Lumped disturbance on d axis and q-axis lumped disturbance for:

[0048]

[0049] Among them, u d (k) is the d-axis voltage actually output by the inverter in the kth cycle; u q (k) is the q-axis voltage actually output by the inverter in the kth cycle; R s is the stator resistance; L s is the dq-axis inductance, ψ is the rotor flux; is the lumped disturbance of the d-axis in the kth period; is the q-axis lumped disturbance of the kth period; β 1 and β 2 are the observer gains, which are:

[0050]

[0051] Among them, z 0 is the double pole of the observer, and its value range is (0,1).

[0052] Further preferably, in S5, when the k+1th cycle is under the first condition, the predicted d-axis current of the k+2th cycle is for:

[0053]

[0054] in, is the q-axis current command of the k-1th cycle.

[0055] In a second aspect, the present invention provides a permanent magnet synchronous motor predictive current control system, comprising: a memory and a processor, wherein the memory stores a computer program, and the processor executes the permanent magnet synchronous motor predictive current control method provided by the first aspect of the present invention when executing the computer program.

[0056] In a third aspect, the present invention further provides a computer-readable storage medium, which includes a stored computer program, wherein when the computer program is executed by a processor, the device where the storage medium is located is controlled to execute the permanent magnet synchronous motor predicted current control method provided in the first aspect of the present invention.

[0057] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0058] 1. The present invention provides a method for predictive current control of a permanent magnet synchronous motor, wherein the control operation to be performed in the next cycle is determined by multi-layer condition judgment in each cycle, and the corresponding control operation is performed in the next cycle; wherein the types of control operations include reducing the absolute value of the d-axis current, reducing the torque, weakening the magnetic field, and increasing the torque. Specifically, when the torque command changes drastically in the medium and high speed range, the voltage command calculated by the existing deadbeat predictive current control method is easy to exceed the voltage output capacity of the inverter, that is, the controller output voltage saturation is easy to occur. In this case, it is difficult for the q-axis current to be excited to its command value by the saturated output voltage within one cycle, which seriously reduces the dynamic performance of the torque rise at medium and high speeds. Based on the physical law that weak magnetic field can alleviate voltage saturation, the present invention proposes a control scheme of first weakening the magnetic field and then increasing the torque. By selecting an optimal weak magnetic field current, the total time spent on weak magnetic field and increasing the torque is minimized. Weak magnetic field can provide more voltage margin for the q-axis voltage, thereby increasing the speed of increasing the q-axis current and torque. The increase in the torque increase speed greatly reduces the time spent on increasing the torque, and the reduction in the time spent on increasing the torque is greater than the time spent on weak magnetic field. Therefore, compared with the existing method of directly increasing the torque control scheme, the control scheme of weakening the magnetic field first and then increasing the torque proposed in the present invention can increase the motor output torque to its command value in a shorter time, effectively improving the torque dynamic performance of the zero-beat predictive current control at medium and high speeds.

[0059] 2. Furthermore, the permanent magnet synchronous motor predictive current control method provided by the present invention also includes calculating the d and q axis voltage instructions for the control operation in the kth cycle, which are used to control the inverter to perform corresponding operations in the k+1th cycle; wherein, when calculating the voltage instructions corresponding to the absolute value of the d-axis current reduction, the weakening magnetic field and the torque increase operations, the limitations of the current increment limit circle are fully considered, which can speed up the subsequent process of completing the corresponding operations and further improve the control efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A flowchart of a control operation for judging the k+1th cycle in the kth cycle provided by an embodiment of the present invention;

[0061] Figure 2 An overall block diagram of the permanent magnet synchronous motor predictive current control provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0063] In order to achieve the above-mentioned object, in a first aspect, the present invention provides a method for predictive current control of a permanent magnet synchronous motor.

[0064] In each cycle, judging and determining the control operation of the next cycle, and performing the corresponding control operation in the next cycle;

[0065] Among them, Figure 1 As shown, the method for judging and determining the control operation of the k+1th cycle in the kth cycle includes:

[0066] S1, sample the signal in the kth cycle and obtain the d-axis current i d (k), q-axis current i q (k), q-axis current command and speed ω(k); k is the index of the sampling period, which is a positive integer;

[0067] S2, based on i d (k), i q (k) and ω(k), using the extended state observer, predict the d-axis current in the k+1th cycle Q-axis current Lumped disturbance on d axis and q-axis lumped disturbance

[0068]

[0069] In an optional implementation, the d-axis current of the k+1th cycle predicted by the extended state observer is Q-axis current Lumped disturbance on d axis and q-axis lumped disturbance for:

[0070]

[0071] Among them, u d (k) is the d-axis voltage actually output by the inverter in the kth cycle; u q(k) is the q-axis voltage actually output by the inverter in the kth cycle; R s is the stator resistance; L s is the dq-axis inductance, ψ is the rotor flux; is the lumped disturbance of the d-axis in the kth period; is the q-axis lumped disturbance of the kth period; β 1 and β 2 are the observer gains, which are:

[0072]

[0073] Among them, z 0 is the double pole of the observer, and its value range is (0,1).

[0074] S3, based on the d-axis and q-axis predicted currents and lumped disturbances of the k+1th cycle, predict the current increment limit circle from the k+1th cycle to the k+2th cycle; wherein the current increment limit circle from the k+1th cycle to the k+2th cycle is the d-axis and q-axis currents in the k+1th cycle after a sampling period T s The circular current area that can be reached in the k+2th cycle after voltage excitation;

[0075] In an optional implementation manner, the center of the current increment limit circle in the dq axis current coordinate system is The expression for the radius r is;

[0076]

[0077] Among them, L s is the dq axis inductance; R s is the stator resistance; ψ is the rotor flux; is the lumped disturbance of the d-axis in the k+1th period; is the q-axis lumped disturbance of the k+1th period; u dc is the DC bus voltage.

[0078] S4. Judgment Is it within the current increment limit circle? If so, the control operation of the k+1th cycle is to reduce the absolute value of the d-axis current and go to S8; otherwise, compare and The size of Then the control operation of the k+1th cycle is to reduce the torque and go to S8; if Then go to S5;

[0079] Specifically, judge Whether it is included in the current increment limit circle: Determine whether it satisfies If so, then determine The current increment limit circle indicates that the q-axis current can be within a sampling period T s Internal Reaching the command value Otherwise, determine It is not within the current increment limit circle, indicating that the q-axis current is not enough to be within a sampling period T s Internal Reaching the command value

[0080] In an optional implementation manner, the above S4 further includes: when When the current increment limit circle is within the range, the d and q axis voltage instructions are calculated in the kth cycle. and The d and q axis voltage instructions The inverter is used to control the inverter to perform an operation of reducing the absolute value of the d-axis current in the k+1th cycle.

[0081] Specifically, the operation of reducing the absolute value of the d-axis current in the k+1th cycle (current minimization operation) includes: giving priority to ensuring the tracking performance of the q-axis current, and then reducing the absolute value of the d-axis current at the fastest rate under the limitation of the current increment limit circle. This operation can reduce the motor winding current increased by weak magnetic field after completing the torque dynamic response to ensure the efficiency of the motor steady-state operation.

[0082] The q-axis voltage in the kth cycle of the above operation is and d-axis voltage Specifically, in order to give priority to the tracking performance of the q-axis current, the q-axis voltage is calculated based on the deadbeat principle.

[0083]

[0084] In order to reduce the absolute value of the d-axis current, the d-axis current command with the minimum absolute value is solved under the restriction of the voltage limit circle.

[0085]

[0086] in, is the maximum stator current amplitude.

[0087] In order to reduce the absolute value of the d-axis current at the fastest rate under the restriction of the current increment limit circle, first determine the current vector Is it within the current increment limit circle? Within the current increment limit circle, the d-axis voltage is calculated according to the deadbeat control principle.

[0088]

[0089] like If it is not within the current increment limit circle, the d-axis voltage is calculated based on the current increment limit circle.

[0090]

[0091] In an optional implementation manner, the above S4 further includes: when is not on the current increment limit circle, and When the d and q axis voltage instructions are calculated in the kth cycle and The d and q axis voltage instructions Used to control the inverter to perform a torque reduction operation in the k+1th cycle;

[0092] Specifically, the operation of reducing the torque in the k+1th cycle includes: keeping the d-axis current unchanged, and making the q-axis current track its command value at the fastest rate under the restriction of the current increment limit circle.

[0093] The q-axis voltage in the kth cycle of the above operation is and d-axis voltage Specifically, the d and q axis voltages are calculated based on the current increment limit circle. and for:

[0094]

[0095] At this time, the d-axis current command of the kth cycle It still maintains the d-axis current command of the previous cycle.

[0096] S5. Under the first condition in the k+1th cycle, predict the d-axis current in the k+2th cycle judge Is it within the current limit circle? If so, go to S6; otherwise, the control operation of the k+1th cycle is to increase the torque, go to S8; wherein the first condition includes: keeping the q-axis current unchanged and weakening the magnetic field at the maximum rate under the limitation of the current increment limit circle;

[0097] In an optional implementation manner, when the k+1th cycle is under the first condition, the d-axis current of the k+2th cycle is predicted. for:

[0098]

[0099] in, is the q-axis current command of the kth cycle.

[0100] In an optional implementation manner, the above S5 further includes: when When not within the current limit circle, calculate the d and q axis voltage instructions in the kth cycle and The d and q axis voltage instructions Used to control the inverter to perform an operation of increasing torque in the k+1th cycle;

[0101] Specifically, the operation of increasing the torque in the k+1th cycle includes: keeping the d-axis current unchanged, and making the q-axis current track its command value at the fastest rate under the restriction of the current increment limit circle.

[0102] The q-axis voltage in the kth cycle of the above operation is and d-axis voltage Specifically, the d and q axis voltages are calculated based on the current increment limit circle. and for:

[0103]

[0104] The d-axis current command of the kth cycle Maintain the d-axis current command of the previous cycle.

[0105] S6, the d-axis current is maintained at Under the condition of Rise to Minimum time required

[0106] The d-axis current is kept at Under the condition of Rise to Minimum time required

[0107] In an alternative embodiment, and All are predicted using the q-axis current rise time prediction formula;

[0108] The current rise time prediction formula is used to predict the time at which the q-axis current changes from the initial value i when the d-axis current remains unchanged. q0 Rise to the final value i q1 Minimum time required

[0109] The following current rise time prediction algorithm is designed to obtain First, the maximum rising rate of the q-axis current when the d-axis current remains unchanged is given:

[0110]

[0111] Next, the second-order Taylor expansion approximation is performed on the above formula:

[0112]

[0113] in:

[0114]

[0115] in, L s is the dq axis inductance; R s is the stator resistance; ψ is the rotor flux.

[0116] Finally, based on the above approximate formula for the maximum rising rate of the q-axis current, by integration, we can obtain the q-axis current from the initial value i q0 Rise to the final value i q1 The predicted value of the minimum time required

[0117]

[0118] Will and Substitute the expression In, get

[0119] Will and Substitute the expression In, get

[0120] S7, comparison and The size of Then the control operation of the k+1th cycle is field weakening, and go to S8; if Then the control operation of the k+1th cycle is to increase the torque, and go to S8;

[0121] In an optional implementation manner, the above S7 further includes: when When the d and q axis voltage instructions are calculated in the kth cycle and The d and q axis voltage instructions Used to control the inverter to perform a magnetic weakening operation in the k+1th cycle;

[0122] Specifically, the operation of weakening magnetic field in the k+1th cycle includes: keeping the q-axis current unchanged, while reducing the d-axis current at the fastest rate under the limitation of the current increment limit circle. The weakening magnetic field in the k+1th cycle can further reduce the total time required for weakening magnetic field and increasing torque, thereby further improving the torque dynamic performance.

[0123] Specifically, the q-axis voltage in the kth cycle of the above operation is and d-axis voltage Completed under control.

[0124] Specifically, the d and q axis voltages are calculated based on the current increment limit circle: and for:

[0125]

[0126] At the same time, update the d-axis current command:

[0127] In an optional implementation manner, the above S7 further includes: when When calculating the d and q axis voltage instructions and The d and q axis voltage instructions Used to control the inverter to perform an operation of increasing torque in the k+1th cycle;

[0128] Specifically, the operation of increasing the torque in the k+1th cycle includes: keeping the d-axis current unchanged, and making the q-axis current track its command value at the fastest rate under the limitation of the current increment limit circle. It should be noted that continuing the field weakening in the k+1th cycle cannot further reduce the total time required for field weakening and increasing the torque, so the field weakening is no longer performed in the k+1th cycle, but the torque is increased.

[0129] Specifically, the q-axis voltage in the kth cycle of the above operation is and d-axis voltage Completed under the control of

[0130] in,

[0131] The d-axis current command of the kth cycle Maintain the d-axis current command of the previous cycle.

[0132] S8. End the judgment of the kth cycle.

[0133] The present invention relates to four control operations, including: current minimization (i.e., reducing the absolute value of the d-axis current), torque reduction, magnetic weakening, and torque increase. In each sampling cycle, the control operation to be performed in the next cycle is determined by multi-layer conditional judgment, and the d-axis and q-axis voltage instructions are calculated for the control operation. Based on the d-axis and q-axis voltage instructions calculated in this sampling cycle, the inverter hardware will output the actual voltage that meets the instructions in the next sampling cycle, thereby realizing the corresponding control operation.

[0134] In summary, the present invention provides a predictive current control method for a permanent magnet synchronous motor based on dynamic magnetic weakening, which judges and determines the control operation of the next cycle through multiple layers of conditions in each cycle, and performs the corresponding control operation in the next cycle. When the torque command changes drastically in the medium and high speed range, it is difficult for the q-axis current to be excited to its command value by the saturated output voltage within one cycle due to the limitation of the saturation of the controller output voltage, which seriously reduces the dynamic performance of the torque increase at medium and high speeds. In the above case, the proposed method first increases the rising rate of the q-axis current through magnetic weakening operation, and then performs the torque increase operation at a larger q-axis current rising rate to determine an optimal magnetic weakening current, so that the total time required for the magnetic weakening operation and the torque increase operation is minimized. The proposed method effectively improves the dynamic performance of the torque increase when the controller output voltage is saturated, and has certain practical value.

[0135] In a second aspect, the present invention provides a permanent magnet synchronous motor predictive current control system, comprising: a memory and a processor, wherein the memory stores a computer program, and the processor executes the permanent magnet synchronous motor predictive current control method provided by the first aspect of the present invention when executing the computer program.

[0136] In an optional implementation, the permanent magnet synchronous motor is a surface mounted permanent magnet synchronous motor (SPMSM), such as Figure 2 As shown, the whole control process involves a deadbeat predictive current controller, an extended state observer, an inverse park transformation module, an SVPWM vector pulse width modulation module, an inverter, a permanent magnet synchronous motor SPMSM, a clark transformation module, a clark transformation module, a park transformation module, a current sensor and a position sensor;

[0137] In the kth cycle, the current sensor is used to sample the three-phase current of the motor, which is converted into the d-axis current i through the Clark transformation module and the Park transformation module. d (k) and q-axis current i q (k); use the position sensor to sample the speed ω(k); obtain the q-axis current command Prediction of the d-axis current in the k+1th cycle by an extended state observer Q-axis current The d-axis lumped disturbance and the q-axis lumped disturbance are then predicted, and the current increment limit circle from the k+1th cycle to the k+2th cycle is predicted. Based on the current increment limit circle, the deadbeat predictive current controller is used to perform the above S4-S8 to predict the control operation of the k+1th cycle and calculate the q-axis voltage of the kth cycle. and d-axis voltage As the voltage command of the k+1th cycle control operation; in the k+1th cycle, based on the q-axis voltage command of the kth cycle and d-axis voltage command The inverter is controlled by generating a switch control signal of the inverter through the inverse park transformation module and the SVPWM vector pulse width modulation module, thereby realizing the corresponding control operation of the SPMSM.

[0138] Among them, the relevant technical solution is the same as the permanent magnet synchronous motor predictive current control method provided in the first aspect of the present invention, and will not be described in detail here.

[0139] In a third aspect, the present invention further provides a computer-readable storage medium, which includes a stored computer program, wherein when the computer program is executed by a processor, the device where the storage medium is located is controlled to execute the permanent magnet synchronous motor predicted current control method provided in the first aspect of the present invention.

[0140] The related technical solution is the same as the permanent magnet synchronous motor predictive current control method provided in the first aspect of the present invention, and will not be described in detail here.

[0141] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for predictive current control of a permanent magnet synchronous motor, characterized in that: include: In each cycle, judging and determining the control operation of the next cycle, and performing the corresponding control operation in the next cycle; The method of judging and determining the control operation of the k+1th cycle in the kth cycle includes: S1, sample the signal in the kth cycle to obtain the d-axis current i d (k), q-axis current i q (k), q-axis current command and speed ω(k); k is the index of the sampling period; S2, based on i d (k), i q (k) and ω(k), using the extended state observer to predict the d-axis current in the k+1th cycle Q-axis current d-axis lumped disturbance and q-axis lumped disturbance; S3, based on the predicted current and lumped disturbance of the d and q axes in the k+1th cycle, predict the current increment limit circle; the current increment limit circle is the current increment of the d and q axes in the k+1th cycle after a sampling period T s The circular current area that can be reached in the k+2th cycle after voltage excitation; S4. Judgment Is it within the current increment limit circle? If so, the control operation of the k+1th cycle is to reduce the absolute value of the d-axis current and go to S8; otherwise, compare and The size of Then the control operation of the k+1th cycle is to reduce the torque and go to S8; if Then go to S5; S5. Under the first condition in the k+1th cycle, predict the d-axis current in the k+2th cycle judge Is it within the current limit circle? If so, go to S6; otherwise, the control operation of the k+1th cycle is to increase the torque, go to S8; the first condition includes: keeping the q-axis current unchanged, and weakening the magnetic field at the maximum rate under the limitation of the current increment limit circle; S6, the d-axis current is maintained at Under the condition of Rise to Minimum time required The d-axis current is kept at Under the condition of Rise to Minimum time required S7, comparison and The size of Then the control operation of the k+1th cycle is field weakening, and go to S8; if Then the control operation of the k+1th cycle is to increase the torque, and go to S8; S8. End the judgment of the kth cycle.

2. The method for predictive current control of a permanent magnet synchronous motor according to claim 1, characterized in that: The center of the current increment limit circle in the dq axis current coordinate system The expression for the radius r is; Among them, L s is the dq axis inductance; R s is the stator resistance; ψ is the rotor flux; is the lumped disturbance of the d-axis in the k+1th period; is the q-axis lumped disturbance of the k+1th period; u dc is the DC bus voltage.

3. The method for predictive current control of a permanent magnet synchronous motor according to claim 2, characterized in that: The S4 also includes: when When the current increment limit circle is within the current increment limit circle, the d and q axis voltage instructions are calculated in the kth cycle. and used to control the inverter to perform an operation of reducing the absolute value of the d-axis current in the k+1th cycle; in, when When within the current increment limit circle, when When it is not within the current increment limit circle, Among them, the d-axis current command of the kth cycle is The calculation expression is: is the maximum stator current amplitude.

4. The method for predictive current control of a permanent magnet synchronous motor according to claim 2, characterized in that: The S4 also includes: when is not within the current increment limit circle, and When the d and q axis voltage instructions are calculated in the kth cycle and Used to control the inverter to perform a torque reduction operation in the k+1th cycle; in, The d-axis current command of the kth cycle Maintain the d-axis current command of the previous cycle.

5. The method for predictive current control of a permanent magnet synchronous motor according to claim 2, characterized in that: The S5 further includes: when When not within the current limit circle, calculate the d and q axis voltage instructions in the kth cycle and Used to control the inverter to perform an operation of increasing torque in the k+1th cycle; in, The d-axis current command of the kth cycle Maintain the d-axis current command of the previous cycle.

6. The method for predictive current control of a permanent magnet synchronous motor according to claim 2, characterized in that: The S7 further includes: when When the d and q axis voltage instructions are calculated in the kth cycle and Used to control the inverter to perform magnetic weakening operation in the k+1th cycle; in, The d-axis current command of the kth cycle The calculation expression is:

7. The method for predictive current control of a permanent magnet synchronous motor according to claim 2, characterized in that: The S7 further includes: when When calculating the d and q axis voltage instructions and Used to control the inverter to perform an operation of increasing torque in the k+1th cycle; in, The d-axis current command of the kth cycle Maintain the d-axis current command of the previous cycle.

8. The method for predictive current control of a permanent magnet synchronous motor according to any one of claims 1 to 7, characterized in that: and All are predicted using the q-axis current rise time prediction formula; The current rise time prediction formula is used to predict the time when the q-axis current changes from the initial value i when the d-axis current remains unchanged. q0 Rise to the final value i q1 Minimum time required Its expression is: in, L s is the dq axis inductance; R s is the stator resistance; ψ is the rotor flux; Will and Substitute the expression In, get Will and Substitute the expression In, get 9. A permanent magnet synchronous motor predictive current control system, characterized in that: include: A memory and a processor, wherein the memory stores a computer program, and the processor executes the permanent magnet synchronous motor predictive current control method according to any one of claims 1 to 8 when executing the computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored computer program, wherein when the computer program is executed by a processor, the device where the storage medium is located is controlled to execute the permanent magnet synchronous motor predictive current control method according to any one of claims 1 to 8.

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