A method and system for controlling a permanent magnet synchronous motor

Abstract

This application discloses a control method and system for a permanent magnet synchronous motor (PMSM). The PMSM control method obtains a first power factor of the PMSM based on a first reference current, wherein the first reference current is the reference current of the current control cycle. Adjustment parameters are determined based on the first power factor and the first reference current. A target reference current is obtained by perturbing the first reference current according to the adjustment parameters, thereby controlling the PMSM. This application obtains the target reference current by applying a perturbation to the reference current and using power factor feedback. This achieves a convergence process through perturbation feedback, adaptively finding the target reference current without requiring a precise motor parameter model. This effectively alleviates the efficiency decline caused by parameter mismatch or operating condition changes in current control strategies, significantly improving steady-state operating efficiency.

Description

Technical Field

[0001] This application relates to the field of electronic technology, specifically to a control method and system for a permanent magnet synchronous motor. Background Technology

[0002] Sensorless control of permanent magnet synchronous motors is crucial for reducing system costs and improving reliability. In applications with less stringent dynamic performance requirements, IF control is a feasible solution for achieving a wide speed range. However, traditional open-loop scalar control suffers from poor damping characteristics and low efficiency; while improved algorithms enhance stability by introducing feedback mechanisms such as frequency compensation, they fail to improve steady-state efficiency.

[0003] Therefore, the technology still needs to be improved and enhanced. Summary of the Invention

[0004] This application provides a control method and system for permanent magnet synchronous motors, which can alleviate the problem of low steady-state efficiency in the current control of permanent magnet synchronous motors.

[0005] This application provides a control method for a permanent magnet synchronous motor, which includes the following steps: The first power factor of the permanent magnet synchronous motor is obtained based on the first reference current; wherein, the first reference current is the reference current of the current control cycle; The adjustment parameters are determined based on the first power factor and the first reference current; The target reference current is obtained by perturbing the first reference current according to the adjustment parameters, so as to control the permanent magnet synchronous motor.

[0006] In some embodiments of the permanent magnet synchronous motor control method, the step of obtaining a first power factor of the permanent magnet synchronous motor based on a first reference current includes: The regulating voltage is obtained based on the first reference current and the actual current, and the regulating voltage is converted into a drive signal to drive the permanent magnet synchronous motor. Sample the three-phase voltage and three-phase current of the permanent magnet synchronous motor, and obtain the active power and reactive power of the permanent magnet synchronous motor based on the three-phase voltage and three-phase current; The first power factor is determined based on active power and reactive power.

[0007] In some embodiments of the permanent magnet synchronous motor control method, the step of determining the adjustment parameters based on a first power factor and a first reference current includes: The power change is determined based on the first power factor and the second power factor; where the second power factor is the power factor of the permanent magnet synchronous motor in the previous control cycle. The change in current is obtained based on the first reference current and the second reference current; wherein, the second reference current is the reference current of the previous control cycle; The adjustment parameters are determined based on the changes in power and current.

[0008] In some embodiments of the permanent magnet synchronous motor control method, the step of perturbing the first reference current according to the adjustment parameters to obtain the target reference current includes: When the absolute value of the adjustment parameter is greater than the preset threshold, the disturbance step value is determined based on the adjustment parameter; The first reference current is perturbed according to the perturbation step value to obtain the third reference current value; The target reference current is determined based on the third reference current value.

[0009] In some embodiments of the permanent magnet synchronous motor control method, the step of determining the disturbance step value based on the adjustment parameter when the absolute value of the adjustment parameter is greater than a preset threshold includes: When the adjustment parameter is greater than the preset adjustment parameter, the disturbance step value is determined to be the first step value. If the adjustment parameter is less than the preset adjustment parameter, the disturbance step value is determined to be the second step value.

[0010] In some embodiments of the permanent magnet synchronous motor control method, the step of perturbing a first reference current according to a perturbation step value to obtain a third reference current value includes: After integrating the perturbation step value, the first reference current is perturbed to obtain the third reference current value.

[0011] In some embodiments of the permanent magnet synchronous motor control method, the step of determining the target reference current based on the third reference current value includes: The third reference current value is determined as the new first reference current, and the process returns to the step of determining the first power factor based on the first reference current until the absolute value of the adjustment parameter is less than or equal to the preset threshold. The first reference current determined when the absolute value of the adjustment parameter is less than or equal to the preset threshold is determined as the target reference current.

[0012] This application embodiment also provides a permanent magnet synchronous motor control system, which includes: The drive control module and the motor control module are used to control the permanent magnet synchronous motor to work according to the first reference current and to obtain the first power factor of the permanent magnet synchronous motor; wherein, the first reference current is the reference current of the current control cycle; The adjustment calculation module is connected to the motor control module and is used to determine the adjustment parameters based on the first power factor and the first reference current. The disturbance control module is connected to both the drive control module and the adjustment calculation module. The disturbance control module is used to disturb the first reference current according to the adjustment parameters to obtain the target reference current, so that the drive control module controls the permanent magnet synchronous motor to work according to the target reference current.

[0013] In some embodiments of the permanent magnet synchronous motor control system, the adjustment calculation module includes: The power calculation unit is connected to the drive control module. The power calculation unit is used to determine the power change based on the first power factor and the second power factor. The second power factor is the power factor of the permanent magnet synchronous motor in the previous control cycle. The current calculation unit is used to obtain the current change based on the first reference current and the second reference current; wherein the second reference current is the reference current of the previous control cycle. The adjustment calculation unit is connected to the power calculation unit and the current calculation unit respectively. The adjustment calculation unit is used to determine the adjustment parameters based on the power change and the current change. In some embodiments of the permanent magnet synchronous motor control system, the disturbance control module includes: The disturbance determination unit is connected to the adjustment calculation unit. The disturbance determination unit is used to determine the disturbance step value based on the adjustment parameter when the absolute value of the adjustment parameter is greater than the preset threshold. The disturbance control unit is connected to the disturbance determination unit. The disturbance control unit is used to disturb the first reference current according to the disturbance step value to obtain the third reference current value, and to determine the third reference current value as the new first reference current and output it to the drive control module, so that the drive control module determines the first power factor according to the first reference current until the absolute value of the adjustment parameter is less than or equal to the preset threshold. The disturbance determination unit is also used to determine the first reference current determined when the absolute value of the adjustment parameter is less than or equal to a preset threshold as the target reference current.

[0014] This application provides a control method and system for a permanent magnet synchronous motor (PMSM). The PMSM control method obtains a first power factor of the PMSM based on a first reference current; determines adjustment parameters based on the first power factor and the first reference current; and obtains a target reference current by perturbing the first reference current according to the adjustment parameters. This application obtains the target reference current by applying a perturbation to the reference current and through power factor feedback, thereby achieving a convergence process through perturbation feedback. It can adaptively find the target reference current without requiring a precise motor parameter model, effectively mitigating the efficiency decline caused by parameter mismatch or operating condition changes in current control strategies and significantly improving steady-state operating efficiency. Attached Figure Description

[0015] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0016] Figure 1 A schematic diagram illustrating the steps of the permanent magnet synchronous motor control method provided in this application embodiment.

[0017] Figure 2 This is a schematic diagram of the control process in the permanent magnet synchronous motor control method provided in the embodiments of this application.

[0018] Figure 3 This is a schematic diagram illustrating the generation of the reference electrical angle in the permanent magnet synchronous motor control method provided in this application embodiment.

[0019] Figure 4 This is a schematic diagram illustrating the generation of adjustment parameters in the permanent magnet synchronous motor control method provided in this application embodiment.

[0020] Figure 5 This is a flowchart illustrating step S300 in the permanent magnet synchronous motor control method provided in this application embodiment.

[0021] Figure 6 This is a schematic diagram of the speed and A-phase current curves in the permanent magnet synchronous motor control method provided in the embodiments of this application.

[0022] Figure 7 This is a structural block diagram of the permanent magnet synchronous motor control system provided in an embodiment of this application.

[0023] Figure 8 The structural block diagram of the adjustment calculation module in the permanent magnet synchronous motor control system provided in the embodiments of this application is shown.

[0024] Figure 9 This is a structural block diagram of the disturbance control module in the permanent magnet synchronous motor control system provided in an embodiment of this application. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Features thus defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0027] Sensorless control of permanent magnet synchronous motors is crucial for reducing system costs and improving reliability. In applications where dynamic performance requirements are not high, IF control is a feasible solution for achieving a wide speed range. IF control refers to I / F control, or Current-to-Frequency Ratio Control. Specifically, during motor startup and low-speed operation, a fixed ratio of current amplitude to frequency is manually set to force the motor to rotate. The current amplitude is the amplitude of a specified sub-current vector, and the frequency is the rotational frequency of the specified sub-current vector. During control, a rotating current with a constant amplitude and a frequency that gradually increases according to a set slope is directly applied to the motor stator. The motor rotor rotates synchronously with the rotating magnetic field, without needing to know the rotor's real-time position.

[0028] In applications where dynamic performance requirements are not high, such as fans, water pumps, and certain compressors, IF control can achieve a wide speed range for starting and running, from zero speed to high speed. However, because it is a purely open-loop control, when the load changes abruptly, the rotor may oscillate or even stop due to loss of synchronization, indicating poor damping characteristics. To overcome load disturbances and prevent loss of synchronization, IF control needs to maintain a large, fixed current, which cannot be adjusted in real time according to the load size, resulting in very low steady-state efficiency.

[0029] This application provides a control method and system for a permanent magnet synchronous motor (PMSM). The PMSM control method obtains a first power factor of the PMSM based on a first reference current, where the first reference current is the reference current for the current control cycle. Adjustment parameters are determined based on the first power factor and the first reference current. A target reference current is obtained by perturbing the first reference current according to the adjustment parameters. The PMSM control method and system in this embodiment obtain the target reference current by applying perturbation to the reference current and using power factor feedback, effectively alleviating the problem of low steady-state efficiency in current PMSM control. Specific embodiments are described below to illustrate the PMSM control method and system in detail.

[0030] Please see Figure 1 The permanent magnet synchronous motor control method provided in this application embodiment includes steps S100~S300, as follows: S100. Obtain the first power factor of the permanent magnet synchronous motor based on the first reference current; wherein, the first reference current is the reference current of the current control cycle.

[0031] Please refer to the following: Figure 2 Here, the first reference current refers to the d-axis current command and q-axis current command given in the current control cycle, i.e., iq* and id*. Typically, to simplify control and achieve unity power factor or maximum torque-to-current ratio, the d-axis reference current id* can be set to 0 (e.g., ...). Figure 2 Only iq* is shown in the image; id* is set to 0 by default. This reference current drives the permanent magnet synchronous motor (e.g., ...). Figure 2 The PMSM (Power Management System) is running and performs real-time sampling calculations to obtain the power factor within the current control cycle.

[0032] Specifically, the step of obtaining the first power factor of the permanent magnet synchronous motor based on the first reference current includes: obtaining an adjustment voltage based on the first reference current and the actual current, and converting the adjustment voltage into a drive signal to drive the permanent magnet synchronous motor; sampling the three-phase voltage and three-phase current of the permanent magnet synchronous motor, and obtaining the active power and reactive power of the permanent magnet synchronous motor based on the three-phase voltage and three-phase current; and determining the first power factor based on the active power and reactive power.

[0033] Wherein, the actual current corresponds to Figure 2 The id and iq values ​​in the code correspond to voltage adjustment. Figure 2 In the context of ud and uq, the three-phase currents correspond to... Figure 2 In this context, ua, ub, and uc (collectively referred to as uabc) correspond to the three-phase currents. Figure 2 The letters ia, ib, and ic (collectively referred to as iabc) in this context.

[0034] Please continue reading. Figure 2 In this embodiment, the first reference current is compared with the actual current obtained through Parker transformation to obtain the current deviation value. This current deviation value is sent to a proportional-integral (PI) controller, which outputs a regulated voltage after calculation. Subsequently, an inverse Parker transformation is performed on the regulated voltage to obtain the voltage components in the two-phase stationary coordinate system. These components are then processed by sinusoidal pulse width modulation (SPWM) to generate a PWM signal, i.e., a drive signal, to drive the three-phase inverter. The inverter outputs three-phase current and three-phase voltage to the permanent magnet synchronous motor, enabling the permanent magnet synchronous motor to operate according to commands.

[0035] During each control cycle, the three-phase voltage and three-phase current are sampled in real time using corresponding voltage and current sensors. The three-phase current and voltage are then used for power calculations to obtain active and reactive power. Simultaneously, the three-phase current undergoes Parker transformation to obtain the actual current, which is fed back to the current loop input to achieve closed-loop control.

[0036] In this context, the entire time segment from acquiring the first reference current to closed-loop regulation to drive the motor, and then to sampling feedback and power factor can be considered as a control cycle of the permanent magnet synchronous motor, while the current control cycle specifically refers to the specific cycle in which the above process is being executed.

[0037] Please see Figure 3 and Figure 4 Furthermore, determining the first power factor based on active and reactive power specifically includes: calculating the apparent power based on active and reactive power, and calculating the first power factor based on active and apparent power. Active power is denoted as P, reactive power as Q, and apparent power as S. The power factor is cosφ1=P / S.

[0038] Please continue reading. Figure 3 In some embodiments, the permanent magnet synchronous motor control method further includes calculating a reference electrical angle based on the active power and a reference angular frequency. Specifically, the active power is filtered by a high-pass filter (HPF), the cutoff angular frequency of which is ω. h The DC component is filtered out by a high-pass filter, and the high-frequency variation component of the active power, i.e., the oscillation component Δ, is extracted. P This oscillation component reflects the rotational speed fluctuation trend of the system. Subsequently, this fluctuation component ΔP is multiplied by the set gain coefficient -K to obtain the frequency adjustment signal Δωe. Finally, this adjustment signal is superimposed on the reference angular frequency ωref to form the actual output angular frequency ωe. This angular frequency is input to an integrator (1 / s) for integration to obtain the reference electrical angle θe. The mathematical expression of its frequency adjustment signal is as follows: .

[0039] Where Δωe corresponds to the frequency adjustment signal, in radians per second; K corresponds to the gain coefficient, which determines the strength of the frequency correction caused by active power fluctuations, and is usually greater than zero; s corresponds to the Laplace operator; ω h This corresponds to the cutoff angular frequency of the high-pass filter, measured in radians per second; P corresponds to the active power, measured in watts.

[0040] In this embodiment, a reference electrical angle θe is obtained in real time by sensorless estimation based on active power fluctuations and fed back to the current loop as the input coordinate angle for Parker transformation and inverse Parker transformation. Working in conjunction with the first reference current, the power factor of the permanent magnet synchronous motor can be obtained in real time without the need for mechanical position sensors, and high power factor closed-loop control can be achieved.

[0041] S200. Determine the adjustment parameters based on the first power factor and the first reference current.

[0042] In this embodiment, after obtaining the first power factor of the permanent magnet synchronous motor based on the first reference current, the adjustment parameter Δk is then calculated and determined based on the first power factor and the first reference current. The step of determining the adjustment parameter Δk based on the first power factor and the first reference current includes: determining the power change based on the first power factor and the second power factor; obtaining the current change based on the first reference current and the second reference current; and determining the adjustment parameter Δk based on the power change and the current change. The second power factor is the power factor of the permanent magnet synchronous motor in the previous control cycle, and the second reference current is the reference current in the previous control cycle.

[0043] Please refer to the following: Figure 4 , specifically, Figure 4 The first power factor is calculated based on the active power P and the apparent power. Then, the second power factor of the previous cycle is obtained through a delay unit, and the power change is calculated based on the first and second power factors. Similarly, after inputting the first reference current, the second reference current of the previous cycle is obtained through a delay unit, and the current change is calculated based on the first and second reference currents. Finally, the adjustment parameter Δk is calculated based on the power change and the current change.

[0044] In this embodiment, within the current control cycle, the first power factor of the permanent magnet synchronous motor is first calculated based on the first reference current. Then, the first power factor is compared with the second power factor from the previous control cycle to obtain the power change. Simultaneously, the difference between the first reference current and the second reference current from the previous control cycle is calculated to obtain the current change. Finally, based on the power change and the current change, the adjustment parameter Δk used to correct the reference current is determined. By calculating the power factor and reference current of two adjacent control cycles, load fluctuations can be detected in real time, facilitating subsequent adaptive adjustments to the control strategy and improving the system's responsiveness to dynamic operating conditions.

[0045] S300: The target reference current is obtained by perturbing the first reference current according to the adjustment parameters, so as to control the permanent magnet synchronous motor.

[0046] In this embodiment, after obtaining the adjustment parameter Δk, a perturbation is applied to the first reference current using this parameter Δk. The adjustment parameter Δk is obtained based on the power change and current change, and its sign represents the gradient direction of the power factor change with the reference current amplitude. Specifically, if the adjustment parameter Δk is greater than 0, it indicates that the power factor increases with the increase of the current amplitude, meaning that the current amplitude is too small and has not yet reached the optimal efficiency point; therefore, the first reference current amplitude needs to be further increased. If the adjustment parameter Δk is less than 0, it indicates that the power factor decreases with the increase of the current amplitude, meaning that the current amplitude is too large and exceeds the optimal efficiency point; therefore, the first reference current amplitude needs to be decreased. Thus, in this embodiment, the first reference current can be adaptively perturbed based on the adjustment parameter Δk to obtain the target reference current and achieve subsequent control of the permanent magnet synchronous motor.

[0047] Please see Figure 5 Specifically, the step of perturbing the first reference current according to the adjustment parameters to obtain the target reference current includes steps S310 to S330, which are as follows: S310. When the absolute value of the adjustment parameter is greater than the preset threshold, determine the disturbance step value based on the adjustment parameter.

[0048] When the absolute value of the adjustment parameter Δk is greater than the preset threshold, it indicates a significant change in the operating state of the permanent magnet synchronous motor. At this point, it is necessary to determine the disturbance step value and, based on this value, to disturb the first reference current in order to approach the optimal current operating point. Specifically, when the adjustment parameter Δk is greater than the preset adjustment parameter, the disturbance step value is determined as the first step value; when the adjustment parameter Δk is less than the preset adjustment parameter, the disturbance step value is determined as the second step value. When the adjustment parameter Δk approaches 0, it indicates that the rate of change of the power factor relative to the reference current approaches zero, indicating that the power factor is at its maximum. Therefore, in this embodiment, the preset adjustment parameter can be set to 0. The first step value is z, and the second step value is -z. Determining the first step value z indicates that the first reference current is disturbed by a forward disturbance step value z; determining the second step value -z indicates that the first reference current is disturbed by a reverse disturbance step value z.

[0049] Specifically, when the adjustment parameter Δk is greater than 0, the first reference current is perturbed in the positive direction, increasing the step value z; when the adjustment parameter Δk is less than 0, the first reference current is perturbed in the negative direction, decreasing the step value z. Thus, by determining the sign of the adjustment parameter Δk, the perturbation direction is always directed towards decreasing the absolute value of the adjustment parameter Δk, thereby enabling the system to converge towards the point of optimal efficiency.

[0050] S320. The first reference current is disturbed according to the disturbance step value to obtain the third reference current value.

[0051] When the absolute value of the adjustment parameter Δk is greater than or equal to a preset threshold, after determining the disturbance step value based on the sign of the adjustment parameter Δk, the first reference current is disturbed according to the disturbance step value to obtain a third reference current value. Specifically, disturbing the first reference current according to the disturbance step value to obtain a third reference current value includes: integrating the disturbance step value, and then disturbing the first reference current according to the integrated disturbance step value to obtain a third reference current value. In this embodiment, by integrating the disturbance step value and then applying a disturbance to the first reference current to obtain a third reference current value, the integration step can accumulate small step disturbances into a continuous and gradual correction amount, thereby eliminating steady-state errors while avoiding sudden changes in the reference current. This helps to suppress oscillations and overshoot introduced by disturbances, making the current regulation process smoother and more stable.

[0052] S330. Determine the target reference current based on the third reference current value.

[0053] Specifically, determining the target reference current based on the third reference current value includes: determining the third reference current value as the new first reference current, and returning to execute the step of determining the first power factor based on the first reference current until the absolute value of the adjustment parameter Δk is less than or equal to a preset threshold; and determining the first reference current determined when the absolute value of the adjustment parameter Δk is less than or equal to the preset threshold as the target reference current.

[0054] In this embodiment, the currently calculated third reference current value is used as the new first reference current, and the process returns to determine the first power factor based on the first reference current. Through this closed-loop iteration, the first reference current is continuously updated, and the corresponding adjustment parameter Δk is recalculated. In each loop, the third reference current after integral perturbation gradually approaches the current value that optimizes system performance, thereby dynamically correcting the operating point and achieving adaptive search for the target reference current. The above iterative process is repeated until the absolute value of the currently calculated adjustment parameter Δk is less than or equal to a preset threshold. At this point, the adjustment parameter Δk approaches 0, and the first reference current used in the current iteration is the optimal or desired operating current. Then, this first reference current is determined as the target reference current value and used as the output of subsequent control commands.

[0055] Please see Figure 6 , Figure 6 This is a schematic diagram of the speed and A-phase current curves in the permanent magnet synchronous motor control method provided in this application embodiment. The horizontal axis in the figure represents time, with the unit being seconds. The vertical axes represent current and speed, respectively. If the initial value of the first reference current is set to 0.2A, that is... Figure 1The iref value is 0.2A, corresponding to the initial value of the first reference current, and the actual current of phase A also stabilizes at 0.2A. Through perturbation optimization based on power factor feedback (i.e., applying an integral perturbation to the first reference current), the system automatically and gradually reduces the reference current, eventually stabilizing the phase A current at approximately 0.06A, while the rotor speed of the permanent magnet synchronous motor remains constant throughout the process. The constant speed means that the electromagnetic torque output by the motor does not decrease, indicating that the same torque can be generated with a smaller current amplitude. In this embodiment, through current perturbation and power factor feedback control, the first reference current is reduced from 0.2A to 0.06A, which reduces losses to a certain extent, and this reduction in losses translates into increased efficiency. This also shows that the embodiment of this application can effectively reduce the steady-state operating losses of the permanent magnet synchronous motor without sacrificing speed stability, alleviating the inefficiency problem caused by unreasonable current distribution in traditional control strategies.

[0056] The permanent magnet synchronous motor control method of this application obtains the target reference current by applying a disturbance to the reference current and feedback of the power factor, thereby realizing the convergence process of the disturbance feedback. It can adaptively find the target reference current without the need for an accurate motor parameter model, thus effectively alleviating the efficiency decline caused by parameter mismatch or operating condition changes in the current control strategy and significantly improving steady-state operating efficiency.

[0057] Please see Figure 7 This application also discloses a permanent magnet synchronous motor control system. The permanent magnet synchronous motor 10 control system includes a drive control module 21, an adjustment calculation module 22, and a disturbance control module 23. The disturbance control module 23 is connected to both the drive control module 21 and the adjustment calculation module 22. The adjustment calculation module 22 is connected to the drive control module 21, and the drive control module 21 is also connected to the permanent magnet synchronous motor 10. The drive control module 21 controls the permanent magnet synchronous motor 10 to operate based on a first reference current and obtains a first power factor of the permanent magnet synchronous motor 10. The first reference current is the reference current of the current control cycle. The adjustment calculation module 22 determines adjustment parameters based on the first power factor and the first reference current. The disturbance control module 23 disturbs the first reference current according to the adjustment parameters to obtain a target reference current, so that the drive control module 21 controls the permanent magnet synchronous motor 10 to operate based on the target reference current.

[0058] In this embodiment, the control system of the permanent magnet synchronous motor 10 obtains the target reference current by applying a disturbance to the reference current and feedback on the power factor. This achieves the convergence process through disturbance feedback, and the target reference current can be adaptively found without the need for an accurate motor parameter model. This effectively alleviates the efficiency decline caused by parameter mismatch or changes in operating conditions in the current control strategy, and significantly improves steady-state operating efficiency.

[0059] Please see Figure 8 In some embodiments, the adjustment calculation module 22 includes a power calculation unit 221, a current calculation unit 222, and an adjustment calculation unit 223. The power calculation unit 221 is connected to the drive control module 21, and the adjustment calculation unit 223 is connected to both the power calculation unit 221 and the current calculation unit 222. The current calculation unit 222 is also connected to the disturbance control module 23. The power calculation unit 221 is used to determine the power change based on a first power factor and a second power factor; wherein the second power factor is the power factor of the permanent magnet synchronous motor 10 in the previous control cycle. The current calculation unit 222 is used to obtain the current change based on a first reference current and a second reference current. The adjustment calculation unit 223 is used to determine the adjustment parameters based on the power change and the current change.

[0060] In this embodiment, the adjustment calculation module 22 calculates the power change by comparing the first power factor with the second power factor from the previous control cycle within the current control cycle. Simultaneously, it subtracts the current change by comparing the first reference current with the current change from the previous control cycle. Finally, based on the power change and current change, it determines the adjustment parameter Δk used to correct the reference current. By calculating the power factor and reference current between two adjacent control cycles, it can perceive load fluctuations in real time, facilitating subsequent adaptive adjustment of the control strategy and improving the system's responsiveness to dynamic operating conditions.

[0061] Please see Figure 9 In some embodiments, the disturbance control module 23 includes a disturbance determination unit 231 and a disturbance control unit 232. The disturbance determination unit 231 is connected to the adjustment calculation unit 223, and the disturbance control unit 232 is connected to the disturbance determination unit 231. Specifically, the disturbance determination unit 231 determines a disturbance step value based on the adjustment parameter when the absolute value of the adjustment parameter is greater than a preset threshold. The disturbance control unit 232 disturbs the first reference current according to the disturbance step value to obtain a third reference current value, and outputs the third reference current value as a new first reference current to the drive control module 21, so that the drive control module 21 determines a first power factor based on the first reference current until the absolute value of the adjustment parameter is less than or equal to the preset threshold. The disturbance determination unit 231 is also used to determine the first reference current determined when the absolute value of the adjustment parameter is less than or equal to the preset threshold as the target reference current.

[0062] Specifically, the disturbance determination unit 231 is used to determine the disturbance step value as a first step value when the adjustment parameter is greater than the preset adjustment parameter, and as a second step value when the adjustment parameter is less than the preset adjustment parameter. The first step value is z, and the second step value is -z. That is, when the adjustment parameter is greater than the preset adjustment parameter, the first reference current is disturbed in the positive direction by a certain value, increasing the reference current amplitude; when the adjustment parameter is less than the preset adjustment parameter, the first reference current is disturbed in the negative direction by a certain value, decreasing the reference current amplitude. In other words, when the preset adjustment parameter is 0, if the adjustment parameter is greater than 0, the first reference current is disturbed in the positive direction, increasing the step value z; if the adjustment parameter is less than 0, the first reference current is disturbed in the negative direction, decreasing the step value z. Thus, by determining the sign direction of the adjustment parameter, the disturbance direction always points in the direction of decreasing the absolute value of the adjustment parameter, thereby enabling the system to converge towards the point of optimal efficiency.

[0063] Specifically, the disturbance control unit 232 is used to determine the disturbance step value based on the positive or negative value of the adjustment parameter when the absolute value of the adjustment parameter is greater than or equal to a preset threshold, and then to disturb the first reference current according to the disturbance step value to obtain a third reference current value. More specifically, the disturbance control unit 232 is also used to disturb the first reference current after integrating the disturbance step value to obtain a third reference current value. In this embodiment, by integrating the disturbance step value and then applying a disturbance to the first reference current to obtain the third reference current value, the integration stage can accumulate small step disturbances into a continuous and gradual correction amount, which helps to suppress oscillations and overshoot introduced by the disturbance, making the current adjustment process smoother and more stable.

[0064] Simultaneously, the disturbance control unit 232 outputs the third reference current value as the new first reference current to the drive control module 21, enabling the drive control module 21 to determine the first power factor based on the first reference current until the absolute value of the adjustment parameter is less than or equal to a preset threshold. Then, the disturbance determination unit 231 determines the first reference current when the absolute value of the adjustment parameter is less than or equal to the preset threshold as the target reference current. In this embodiment, through closed-loop iteration, the first reference current is continuously updated, and the corresponding adjustment parameters are recalculated. In each cycle, the third reference current after integral disturbance gradually approaches the current value that optimizes system performance, thereby dynamically correcting the operating point and achieving adaptive search for the target reference current. This iterative process is repeated until the absolute value of the currently calculated adjustment parameter is less than or equal to the preset threshold; then, the first reference current used in the current iteration is the optimal or desired operating current.

[0065] The permanent magnet synchronous motor 10 control system in this application obtains the target reference current by applying a disturbance to the reference current and feedback on the power factor, thereby realizing the convergence process of the disturbance feedback. It can adaptively find the target reference current without the need for an accurate motor parameter model, thus effectively alleviating the efficiency decline caused by parameter mismatch or changes in operating conditions in the current control strategy and significantly improving steady-state operating efficiency.

[0066] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0067] The permanent magnet synchronous motor control method and system provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A control method for a permanent magnet synchronous motor, characterized in that, The permanent magnet synchronous motor control method includes the following steps: The first power factor of the permanent magnet synchronous motor is obtained based on the first reference current; wherein, the first reference current is the reference current of the current control cycle; The adjustment parameters are determined based on the first power factor and the first reference current; The target reference current is obtained by perturbing the first reference current according to the adjustment parameters, so as to control the permanent magnet synchronous motor.

2. The permanent magnet synchronous motor control method according to claim 1, characterized in that, The step of obtaining the first power factor of the permanent magnet synchronous motor based on the first reference current includes: The adjustment voltage is obtained based on the first reference current and the actual current, and the adjustment voltage is converted into a drive signal to drive the permanent magnet synchronous motor; The three-phase voltage and three-phase current of the permanent magnet synchronous motor are sampled, and the active power and reactive power of the permanent magnet synchronous motor are obtained based on the three-phase voltage and three-phase current. The first power factor is determined based on the active power and the reactive power.

3. The permanent magnet synchronous motor control method according to claim 1, characterized in that, The step of determining the adjustment parameters based on the first power factor and the first reference current includes: The power change is determined based on the first power factor and the second power factor; wherein the second power factor is the power factor of the permanent magnet synchronous motor in the previous control cycle; The change in current is obtained based on the first reference current and the second reference current; wherein, the second reference current is the reference current of the previous control cycle; The adjustment parameters are determined based on the power change and the current change.

4. The permanent magnet synchronous motor control method according to claim 1, characterized in that, The step of perturbing the first reference current according to the adjustment parameters to obtain the target reference current includes: When the absolute value of the adjustment parameter is greater than a preset threshold, the disturbance step value is determined according to the adjustment parameter; The first reference current is perturbed according to the perturbation step value to obtain the third reference current value; The target reference current is determined based on the third reference current value.

5. The permanent magnet synchronous motor control method according to claim 4, characterized in that, The step of determining the disturbance step value based on the adjustment parameter when the absolute value of the adjustment parameter is greater than a preset threshold includes: When the adjustment parameter is greater than the preset adjustment parameter, the disturbance step value is determined to be the first step value. When the adjustment parameter is less than the preset adjustment parameter, the disturbance step value is determined to be the second step value.

6. The permanent magnet synchronous motor control method according to claim 4, characterized in that, The step of perturbing the first reference current according to the perturbation step value to obtain the third reference current value includes: The disturbance step value is integrated, and the first reference current is disturbed according to the integrated disturbance step value to obtain the third reference current value.

7. The permanent magnet synchronous motor control method according to claim 4, characterized in that, The step of determining the target reference current based on the third reference current value includes: The third reference current value is determined as the new first reference current, and the process returns to the step of determining the first power factor based on the first reference current until the absolute value of the adjustment parameter is less than or equal to a preset threshold. The first reference current determined when the absolute value of the adjustment parameter is less than or equal to the preset threshold is determined as the target reference current.

8. A permanent magnet synchronous motor control system, characterized in that, The permanent magnet synchronous motor control system includes: A drive control module is configured to control the operation of a permanent magnet synchronous motor based on a first reference current and to obtain a first power factor of the permanent magnet synchronous motor; wherein the first reference current is the reference current of the current control cycle. An adjustment calculation module is connected to the drive control module, and the adjustment calculation module is used to determine adjustment parameters based on the first power factor and the first reference current; A disturbance control module is provided, which is connected to both the drive control module and the adjustment calculation module. The disturbance control module is used to disturb the first reference current according to the adjustment parameters to obtain a target reference current, so that the drive control module controls the permanent magnet synchronous motor to work according to the target reference current.

9. The permanent magnet synchronous motor control system according to claim 8, characterized in that, The adjustment calculation module includes: A power calculation unit is connected to the drive control module. The power calculation unit is used to determine the power change based on the first power factor and the second power factor. The second power factor is the power factor of the permanent magnet synchronous motor in the previous control cycle. A current calculation unit is used to obtain the current change based on the first reference current and the second reference current; wherein the second reference current is the reference current of the previous control cycle; An adjustment calculation unit is provided, which is connected to the power calculation unit and the current calculation unit respectively. The adjustment calculation unit is used to determine the adjustment parameters based on the power change and the current change.

10. The permanent magnet synchronous motor control system according to claim 9, characterized in that, The disturbance control module includes: A disturbance determination unit is connected to the adjustment calculation unit. The disturbance determination unit is used to determine a disturbance step value based on the adjustment parameter when the absolute value of the adjustment parameter is greater than a preset threshold. A disturbance control unit is connected to the disturbance determination unit. The disturbance control unit is used to disturb the first reference current according to the disturbance step value to obtain a third reference current value, and to determine the third reference current value as a new first reference current and output it to the drive control module, so that the drive control module determines a first power factor according to the first reference current until the absolute value of the adjustment parameter is less than or equal to a preset threshold. The disturbance determination unit is further configured to determine the first reference current determined when the absolute value of the adjustment parameter is less than or equal to the preset threshold as the target reference current.

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