A method and system for predictive current control of a permanent magnet synchronous motor

Abstract

The present invention discloses a method and system for predictive current control of a permanent magnet synchronous motor, belonging to the technical field of permanent magnet synchronous motor control. When the torque instruction changes drastically in the medium and high speed range, the zero-beat predictive current control is very likely to cause output voltage saturation, resulting in the q-axis current being difficult to be excited to its instruction value by the saturated output voltage within one sampling cycle, thereby seriously reducing the dynamic performance of torque increase at medium and high speeds. To this end, the present invention first increases the rising rate of the q-axis current through a weak magnetic operation under the above circumstances, and then performs a torque increase operation at a greater q-axis current rising rate. An optimal weak magnetic current is determined based on the q-axis current rise time prediction algorithm, so that the total time required for the weak magnetic operation and the torque increase operation is minimized, which can effectively improve the torque dynamic performance of the zero-beat predictive current control at medium and high speeds.

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 motors (SPMSMs) are widely used in servo control systems due to their high torque density, high efficiency, and excellent control performance. In recent years, due to the pursuit of ultra-fast dynamic response performance, deadbeat predictive current control has attracted widespread attention and has been deeply studied.

[0003] If the bus voltage is sufficient, deadbeat predictive current control can theoretically achieve two-cycle deadbeat response performance. However, when the torque command changes dramatically in the medium- and high-speed range, the reference voltage command calculated by the deadbeat predictive current controller can easily exceed the bus voltage limit, causing the controller output to saturate. This makes it difficult for the q-axis current to be driven to its command value by the saturated output voltage within a single cycle, severely reducing the dynamic performance of torque rise at medium and high speeds. Therefore, it is of great significance to urgently develop a method based on deadbeat predictive current control to improve the dynamic torque performance at medium and high speeds. Summary of the Invention

[0004] In response to 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, the purpose of which is to improve the torque dynamic performance of the zero-beat predictive current control at medium and high speeds.

[0005] To achieve the above objectives, 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, the control operation of the next cycle is judged and determined, and the corresponding control operation is performed in the next cycle;

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

[0008] S1, perform signal sampling in the kth cycle to obtain the d-axis current i d (k), q-axis current i q (k), q-axis current command and the 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 to 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 in 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+1 cycle is to reduce the absolute value of the d-axis current and go to S8; otherwise, compare and The size of The control operation of the k+1 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+1 cycle is to increase the torque, and go to S8; wherein the first condition includes: keeping the q-axis current unchanged and weakening the magnetic field at the maximum rate within the current increment limit circle;

[0013] S6, the d-axis current is kept at Under the condition of the current increment limit circle, it is predicted that the q-axis current will be reduced from Rise to Minimum time required

[0014] The d-axis current is kept at Under the condition of the current increment limit circle, it is predicted that the q-axis current will be reduced from Rise to Minimum time required

[0015] S7, comparison and The size of The control operation of the k+1 cycle is field weakening, and the process goes to S8; if 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 d-axis lumped disturbance of 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 the current increment limit circle is within the range,

[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] 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] 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] 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] 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 it takes for the q-axis current to rise 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 expressions In, get

[0046] Will and Substitute expressions 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 d-axis lumped disturbance 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 d-axis lumped disturbance of the k-th period; is the q-axis lumped disturbance of the k-th period; β1 and β2 are the observer gains, respectively:

[0050]

[0051] Among them, z0 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 d-axis current of the k+2th cycle is predicted to be 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 also provides a computer-readable storage medium, which includes a stored computer program, wherein when the computer program is executed by the 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 predictive current control method for a permanent magnet synchronous motor. In each cycle, the control operation to be executed in the next cycle is determined through multi-layer conditional judgment, and the corresponding control operation is executed in the next cycle. The types of control operations include reducing the absolute value of the d-axis current, reducing torque, field weakening, and increasing torque. Specifically, when the torque command changes dramatically within the medium- and high-speed range, the voltage command calculated by existing deadbeat predictive current control methods can easily exceed the voltage output capability of the inverter, which means that the controller output voltage is prone to saturation. In this case, the q-axis current is difficult to be driven to its command value by the saturated output voltage within a single cycle, severely reducing the dynamic performance of torque rise at medium- and high-speed conditions. Based on the physical principle that field weakening can alleviate voltage saturation, the present invention proposes a control scheme that first weakens the field and then increases the torque. By selecting an optimal field weakening current, the total time spent on field weakening and increasing torque is minimized. Field weakening provides more voltage margin for the q-axis voltage, thereby increasing the speed of q-axis current and torque increase. The increased torque increase speed significantly reduces the time spent on torque increase, and the reduction in torque increase time is greater than the time spent on field weakening. Therefore, compared with the existing method of directly increasing the torque control scheme, the control scheme of first weakening the magnetic field 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-axis 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 operations of reducing the absolute value of the d-axis current, weakening the magnetic field, and increasing the torque, 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 determining the k+1th cycle in the kth cycle provided by an embodiment of the present invention;

[0061] Figure 2This is 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 objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining 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 may be combined with each other as long as they do not conflict with each other.

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

[0064] In each cycle, the control operation of the next cycle is judged and determined, and the corresponding control operation is performed in the next cycle;

[0065] Among them, such as 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, perform signal sampling in the kth cycle to obtain the d-axis current i d (k), q-axis current i q (k), q-axis current command and the 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 to predict the d-axis current in the k+1th cycle q-axis current d-axis lumped disturbance and q-axis lumped disturbance

[0068]

[0069] In an optional embodiment, the d-axis current of the k+1th cycle predicted by the extended state observer is q-axis current d-axis lumped disturbance 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; Rs is the stator resistance; L s is the dq-axis inductance, ψ is the rotor flux; is the d-axis lumped disturbance of the k-th period; is the q-axis lumped disturbance of the k-th period; β1 and β2 are the observer gains, respectively:

[0072]

[0073] Among them, z0 is the double pole of the observer, and its value range is (0,1).

[0074] S3. Based on the predicted d-axis and q-axis currents and the lumped disturbance in 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 d-axis lumped disturbance of 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+1 cycle is to reduce the absolute value of the d-axis current and go to S8; otherwise, compare and The size of The control operation of the k+1 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 meets If so, then determine The current increment limit circle indicates that the q-axis current can be within a sampling period T s Internal Reach the command value Otherwise, judge It is not within the current increment limit circle, indicating that the q-axis current is not enough in a sampling period T s Internal Reach the command value

[0080] In an optional embodiment, 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) involves prioritizing q-axis current tracking performance and then reducing the absolute value of the d-axis current at the fastest rate within the constraints of the current increment limit circle. This operation reduces the increase in motor winding current caused by field weakening after completing the torque dynamic response, thereby ensuring the motor's steady-state efficiency.

[0082] The q-axis voltage in the kth cycle of the above operation is and d-axis voltage Specifically, in order to prioritize 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 instruction 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 limitation 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 embodiment, 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 constraint 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+1 cycle is to increase the torque, and go to S8; wherein the first condition includes: keeping the q-axis current unchanged and weakening the magnetic field at the maximum rate within the current increment limit circle;

[0097] In an optional embodiment, 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] 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 kept at Under the condition of the current increment limit circle, it is predicted that the q-axis current will be reduced from Rise to Minimum time required

[0106] The d-axis current is kept at Under the condition of the current increment limit circle, it is predicted that the q-axis current will be reduced from 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 it takes for the q-axis current to rise 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, perform a second-order Taylor expansion approximation 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, the q-axis current can be obtained by integration from the initial value i q0 Rise to the final value i q1 The predicted minimum time required

[0117]

[0118] Will and Substitute expressions In, get

[0119] Will and Substitute expressions In, get

[0120] S7, comparison and The size of The control operation of the k+1 cycle is field weakening, and the process goes to S8; if 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 magnetic weakening operation in the k+1th cycle;

[0122] Specifically, field weakening during the k+1th cycle involves maintaining the q-axis current constant while simultaneously reducing the d-axis current at the fastest rate within the current increment limit circle. Field weakening during the k+1th cycle further reduces the total time required for field weakening and torque increase, thereby further improving torque dynamics.

[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 torque increase operation in the k+1th cycle involves maintaining the d-axis current constant while simultaneously tracking the q-axis current to its command value at the fastest rate within the constraints of the current increment limit circle. It should be noted that continuing field weakening in the k+1th cycle does not further reduce the total time required for field weakening and torque increase. Therefore, field weakening is no longer performed in the k+1th cycle, and torque increase is initiated instead.

[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] 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 involves four control operations: current minimization (i.e., reducing the absolute value of the d-axis current), torque reduction, field weakening, and torque boosting. During each sampling cycle, a multi-layered conditional judgment is performed to determine the control operation to be executed in the next cycle, and d- and q-axis voltage commands are calculated for that control operation. Based on the d- and q-axis voltage commands calculated during the current sampling cycle, the inverter hardware will output the actual voltage that meets the commands during the next sampling cycle, thereby implementing 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 controller output voltage saturation, which seriously reduces the dynamic performance of the torque increase at medium and high speeds. In the above situation, 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 under the condition of controller output voltage saturation, 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 embodiment, the permanent magnet synchronous motor is a surface mounted permanent magnet synchronous motor (SPMSM), such as Figure 2 As shown in the figure, the whole control process involves the deadbeat prediction current controller, extended state observer, inverse park transformation module, SVPWM vector pulse width modulation module, inverter, permanent magnet synchronous motor SPMSM, clark transformation module, clark transformation module, park transformation module, current sensor and position sensor;

[0137] In the kth cycle, the motor three-phase current is sampled by the current sensor and 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 instruction Predicting the d-axis current in the k+1th cycle via 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 execute 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 instruction of the control operation of the k+1th cycle; in the k+1th cycle, based on the q-axis voltage instruction of the kth cycle and d-axis voltage command The inverter is controlled by generating the switching 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 by the first aspect of the present invention, and will not be described in detail here.

[0139] In a third aspect, the present invention also provides a computer-readable storage medium, which includes a stored computer program, wherein when the computer program is executed by the 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 merely 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 scope of protection 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, the control operation of the next cycle is judged and determined, and the corresponding control operation is performed in the next cycle; The method for judging and determining the control operation of the k+1th cycle in the kth cycle includes: S1, perform signal sampling in the kth cycle to obtain the d-axis current i d (k), q-axis current i q (k), q-axis current command and the 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 d-axis and q-axis predicted currents and lumped disturbances in the k+1th cycle, predict the current increment limit circle; the current increment limit circle is the current of the d-axis and q-axis 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 The control operation of the k+1 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+1 cycle is to increase the torque, and go to S8; the first condition includes: keeping the q-axis current unchanged and weakening the magnetic field at the maximum rate within the limit of the current increment limit circle; S6, the d-axis current is kept at Under the condition of the current increment limit circle, it is predicted that the q-axis current will be reduced from Rise to Minimum time required The d-axis current is kept at Under the condition of the current increment limit circle, it is predicted that the q-axis current will be reduced from Rise to Minimum time required S7, comparison and The size of The control operation of the k+1 cycle is field weakening, and the process goes to S8; if 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, wherein: 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 d-axis lumped disturbance of 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, wherein: The S4 further includes: When the current increment limit circle is within the limit, 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, wherein: The S4 further includes: 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, 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, wherein: The S5 further includes: 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, 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, wherein: The S7 further includes: 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, 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, wherein: The S7 further includes: 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, 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 to 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 expressions In, get Will and Substitute expressions 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 when the processor executes the computer program, the permanent magnet synchronous motor predictive current control method according to any one of claims 1 to 8 is executed.

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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