阅读说明：本技术 一种永磁同步电机转矩控制装置 (Torque control device of permanent magnet synchronous motor ) 是由 李德正 上官文斌 赵学智 蒋开洪 于 2020-12-22 设计创作，主要内容包括：本发明公开了一种永磁同步电机转矩控制装置与方法,包括：电流前馈控制器、q轴电流反馈控制器和d轴电流反馈控制器、电阻、电感估算器、反馈控制器最优参数决策器、位置传感器、电压变换器、永磁同步电机、电流变换器。在本发明的永磁同步电机转矩控制装置中,所述电流前馈控制器用于降低永磁同步电机的电流扰动,同时提高电机的响应速度。所述q轴电流反馈控制器和d轴电流反馈控制器,用于永磁同步电机的电流反馈控制,降低电机的稳态误差,提高电机的稳定性能和鲁棒性能。所述电流前馈控制器传递函数采用二阶结构和所述电阻、电感估算器与所述反馈控制器最优参数决策器采用查表模块,易于进行嵌入式实现。(The invention discloses a device and a method for controlling torque of a permanent magnet synchronous motor, wherein the device comprises the following steps: the device comprises a current feedforward controller, a q-axis current feedback controller, a d-axis current feedback controller, a resistor, an inductance estimator, a feedback controller optimal parameter decision maker, a position sensor, a voltage converter, a permanent magnet synchronous motor and a current converter. In the torque control device of the permanent magnet synchronous motor, the current feedforward controller is used for reducing the current disturbance of the permanent magnet synchronous motor and simultaneously improving the response speed of the motor. The q-axis current feedback controller and the d-axis current feedback controller are used for current feedback control of the permanent magnet synchronous motor, so that the steady-state error of the motor is reduced, and the stability and the robustness of the motor are improved. The current feedforward controller transfer function adopts a second-order structure, and the resistor, the inductance estimator and the feedback controller optimal parameter decision maker adopt a table look-up module, so that the embedded realization is easy.)

1. A permanent magnet synchronous motor torque control device is used for permanent magnet synchronous motor control, and is characterized by comprising:

a current feedforward controller with a target current signal i as an input signal_cmdThe output signal is a q-axis target current i_q；

A q-axis current feedback controller, wherein the input signal of the q-axis current feedback controller is the q-axis target current i_qAnd q-axis actual current i_q ^*The output signal is a q-axis targetVoltage u_q；

A d-axis current feedback controller, wherein the input signal of the d-axis current feedback controller is a d-axis target current i_dAnd d-axis actual current i_d ^*Is output as a d-axis target voltage u_d；

A resistance and inductance estimator, wherein the input signal of the resistance and inductance estimator is the q-axis target current i_qQ-axis actual current i_q ^*The d-axis target current i_dAnd the d-axis actual current i_d ^*The output signals are an estimated resistance R and an inductance L;

the optimal parameter decision maker of the feedback controller inputs signals of the estimated resistance R and the inductance L and outputs signals of the optimal parameter decision maker of the feedback controller, wherein the output signals are q-axis feedback control proportional coefficient K_{p_q}And q-axis feedback control integral coefficient K_{i_q}D-axis feedback control proportionality coefficient K_{p_d}And d-axis feedback control integral coefficient K_{i_d}；

The position sensor is used for measuring the position of a rotor of the permanent magnet synchronous motor, and an output signal is a rotation angle theta;

a voltage converter with input signal of the q-axis target voltage u_qD-axis target voltage u_dAnd the rotation angle theta, and outputting a signal which is the three-phase voltage of the permanent magnet synchronous motor;

the permanent magnet synchronous motor inputs the three-phase voltage and outputs a three-phase current i_a、i_bAnd i_c(ii) a And

a current converter with input signals of the three-phase current i_a、i_b、i_cAnd the rotation angle theta, and the output signal is the actual current i of the q axis_q ^*And d-axis actual current

2. The PMSM torque control device of claim 1, wherein the current feedforward controller is designed with the goals of:

wherein Q is_ff(s) is the transfer function of the current feedforward controller, G_{I_eq}(s) is a q-axis target current i_qFor input and q-axis actual current i_q ^*Is the transfer function of the output permanent magnet synchronous motor.

3. The PMSM torque control device of claim 2, wherein the current feed-forward controller has a transfer function of:

where pole p₁And p₂Zero point z₁And z₂By optimizing the design objective, S is a sign in the transfer function representing the complex field.

4. The PMSM torque control device of claim 1, further comprising a first summing module, a second summing module, and an inverse number taking module,

the first summation module sums a q-axis target current i_qAnd q-axis actual current i_q ^*The difference value is obtained by summing the values obtained by the inverse number module 103,

the second summation module sums a d-axis target current i_dAnd d-axis actual current i_d ^*And the difference value is obtained by summing the values obtained by the inverse number module 103.

5. The PMSM torque control device of claim 1, wherein the resistance and inductance estimator includes a q-axis current lookup module and a d-axis current lookup module, a resistance lookup module and an inductance lookup module,

the q-axis current look-up table module inputs a signal which is the q-axis target current i_qWith said q-axis actual current i_q ^*The output signal is a first parameter Q;

the d-axis current look-up table module inputs a signal as the d-axis target current i_dAnd the d-axis actual currentThe output signal is a second parameter D;

the resistance look-up table module inputs signals of the first parameter Q and the second parameter D and outputs the signals of the first parameter Q and the second parameter D as the estimated resistance R;

the inductance look-up table module inputs signals of the first parameter Q and the second parameter D and outputs the input signals of the first parameter Q and the second parameter D as the estimated inductance L.

6. The PMSM torque control device of claim 1, wherein the feedback controller optimal parameter decision-maker comprises K_{p_q}Table look-up module, K_{i_q}Table look-up module, K_{p_d}Table look-up module and K_{i_d}A table look-up module for searching the table,

K_{p_q}the table look-up module inputs signals of the estimation resistance R and the estimation inductance L and outputs signals of the q-axis feedback control proportionality coefficient K_{p_q}；

K_{i_q}The table look-up module inputs signals of the estimation resistance R and the estimation inductance L and outputs signals of the q-axis feedback control integral coefficient K_{i_q}；

K_{p_d}The table look-up module inputs signals of the estimated resistance R and the estimated inductance L and outputs signals of the d-axis feedback control proportionality coefficient K_{p_d}；

K_{i_d}The table look-up module inputs signals of the estimation resistance R and the estimation inductance L and outputs signals of the d-axis feedback control integral coefficient K_{i_d}。

7. The PMSM torque control device of claim 1, wherein the voltage converter includes a Park inverse transform, SVPWM and inverter,

the q-axis target voltage u_qAnd the d-axis target voltage u_dCarrying out Park inverse transformation by using the rotation angle theta to obtain alpha phase voltage u_αAnd beta phase voltage u_βAlpha phase voltage u_αAnd beta phase voltage u_βAnd obtaining the three-phase voltage of the permanent magnet synchronous motor through SVPWM and an inverter.

8. The PMSM torque control device of claim 1, wherein the current converters include Clarke conversion and Park conversion,

the three-phase current i_a、i_bAnd i_cObtaining alpha phase current i by Clarke transformation_αBeta phase current i_βThen, the alpha phase current i is converted into the alpha phase current by using the rotation angle theta_αBeta phase current i_βCarrying out Park conversion to obtain the q-axis actual current i_q ^*And d-axis actual current i_d ^*。

9. The PMSM torque control device of claim 1, wherein the q-axis current feedback controller has a transfer function of:

10. the PMSM torque control device of claim 1, wherein the transfer function of the d-axis current feedback controller is:

。

Technical Field

The invention relates to the technical field of synchronous motor control, in particular to a torque control device of a permanent magnet synchronous motor.

Background

Permanent Magnet Synchronous Motors (PMSM) have the remarkable advantages of low noise, high power density, wide rotating speed range, energy conservation and the like, and are widely applied to the fields of new energy automobiles, robot servo, household appliances and the like.

At present, a Field Oriented Control (FOC) is generally adopted for controlling a permanent magnet synchronous motor, that is, a space magnetic Field vector generated by three-phase alternating current of a stator is controlled to drive a rotor to rotate in a magnetic Field to form torque. To obtain Maximum current utilization efficiency, Maximum Torque to current ratio control (MTPA) is generally applied on the basis of FOC. The MTPA can be used for positively correlating the output torque of the motor and the input current amplitude. Therefore, the torque output by the motor can be controlled only by adjusting the amplitude of the current. The current, speed and position of the motor are typically regulated by a cascaded current loop, speed loop and position loop of three PI controllers. The current loop is the most basic for motor control.

In the control of the permanent magnet synchronous motor, the torque fluctuation of the motor is an important performance index for measuring the control effect of the motor. The torque fluctuation of the motor is transmitted to a driving load through the speed reducing mechanism, and the speed reducing mechanism generally has the functions of reducing speed and increasing torque, so that the torque fluctuation is transmitted to the whole system after being amplified, the system vibrates at a low speed, noise is generated at a high speed, and adverse effects are generated. In the fields of new energy automobiles and automobile electric control driving systems, the torque fluctuation of a motor can influence the NVH performance of the automobile, and particularly in an electric power steering system, the torque fluctuation of the motor can be transmitted to a steering wheel, so that a driver feels the shake of the steering wheel when steering, and the steering comfort is influenced; in the robot servo field, the torque fluctuation of a motor can influence the precision of servo control; in the household electrical appliance field, the torque fluctuation of the motor can cause the household electrical appliance to generate undesirable vibration and noise, the comfort of a household electrical appliance user is easily influenced, and the service life of the household electrical appliance can be reduced by colleagues.

For torque fluctuation control research of a permanent magnet synchronous motor, an early control strategy is mainly a current waveform optimization method, belongs to open-loop control, and needs to be established on the basis of fully knowing the torque characteristics of a controlled motor. The realization of the method needs a large amount of off-line tests and calculation, has strong dependence on motor parameters, operation conditions and environment, limited application range and longer time for motor control research and development. The later control strategy is mainly PI control, belongs to closed-loop control, and has better robustness. But since the control requires the use of feedback to the current, the response speed of the motor is affected. And under the influence of uncertain factors such as parameter variation, environmental disturbance and the like, the traditional PI control is difficult to have a good control effect under all conditions. In order to consider both the suppression of the torque fluctuation of the permanent magnet synchronous motor and the dynamic response performance of the motor and simultaneously integrate the consideration of the research and development time of the motor and the embedded realization difficulty degree of the control strategy, a torque control device of the permanent magnet synchronous motor, which has the advantages that the controller is easy to realize in an embedded manner, the parameters can be simply and conveniently obtained in the forward direction, the torque fluctuation of the motor can be suppressed, and the motor can respond quickly, is urgently needed.

Disclosure of Invention

The invention aims to provide a permanent magnet synchronous motor torque control device, which can restrain torque fluctuation of a permanent magnet synchronous motor, can make the permanent magnet synchronous motor respond quickly, and is easy to realize in an embedded mode by a controller used by the control device and can obtain parameters in a forward direction simply and conveniently. In order to solve the technical problem, the invention provides a torque control device of a permanent magnet synchronous motor. In order to achieve the purposes of restraining the torque fluctuation of the permanent magnet synchronous motor and improving the response speed of the motor, the invention adopts the technical scheme that:

a permanent magnet synchronous motor torque control device for permanent magnet synchronous motor control, comprising:

a current feedforward controller with a target current signal i as an input signal_cmdThe output signal is a q-axis target current i_q；

A q-axis current feedback controller, wherein the input signal of the q-axis current feedback controller is the q-axis target current i_qAnd q-axis actual current i_q ^*Is output as a q-axis target voltage u_q；

A d-axis current feedback controller, wherein the input signal of the d-axis current feedback controller is a d-axis target current i_dAnd d-axis actual current i_d ^*Is output as a d-axis target voltage u_d；

A resistance and inductance estimator, wherein the input signal of the resistance and inductance estimator is the q-axis target current i_qQ-axis actual current i_q ^*The d-axis target current i_dAnd the d-axis actual current i_d ^*The output signals are an estimated resistance R and an inductance L;

the optimal parameter decision maker of the feedback controller inputs signals of the estimated resistance R and the inductance L and outputs signals of the optimal parameter decision maker of the feedback controller, wherein the output signals are q-axis feedback control proportional coefficient K_{p_q}And q-axis feedback control integral coefficient K_{i_q}D-axis feedback control proportionality coefficient K_{p_d}And d-axis feedback control integral coefficient K_{i_d}；

The position sensor is used for measuring the position of a rotor of the permanent magnet synchronous motor, and an output signal is a rotation angle theta;

a voltage converter with input signal of the q-axis target voltage u_qD-axis target voltage u_dAnd the rotation angle theta, and outputting a signal which is the three-phase voltage of the permanent magnet synchronous motor;

permanent magnet synchronous motor, permanent magnet synchronous motorThe input signal is the three-phase voltage, and the output signal is three-phase current i_a、i_bAnd i_c(ii) a And

a current converter with input signals of the three-phase current i_a、i_b、i_cAnd the rotation angle theta, and the output signal is the actual current i of the q axis_q ^*And d-axis actual current i_d ^*。

Further, the design goals of the current feedforward controller are as follows:

wherein Q is_ff(s) is the transfer function of the current feedforward controller, G_{I_eq}(s) is a q-axis target current i_qFor input and q-axis actual current i_q ^*Is the transfer function of the output permanent magnet synchronous motor.

Further, the transfer function of the current feedforward controller is:

where pole p₁And p₂Zero point z₁And z₂By optimizing the design objective.

Further comprises a first summation module, a second summation module and an inverse number taking module,

the first summation module sums a q-axis target current i_qAnd q-axis actual current i_q ^*The difference value is obtained by summing the values obtained by the inverse number module 103,

the second summation module sums a d-axis target current i_dAnd d-axis actual current i_d ^*And the difference value is obtained by summing the values obtained by the inverse number module 103.

Furthermore, the resistance and inductance estimator comprises a q-axis current lookup module, a d-axis current lookup module and a resistorThe q-axis current lookup module inputs a signal as the q-axis target current i_qWith said q-axis actual current i_q ^*The output signal is the first parameter Q. The d-axis current look-up table module inputs a signal as the d-axis target current i_dAnd the d-axis actual current i_d ^*And the output signal is a second parameter D. The resistance look-up table module inputs signals of the first parameter Q and the second parameter D and outputs the signals of the first parameter Q and the second parameter D as the estimated resistance R. The inductance look-up table module inputs signals of the first parameter Q and the second parameter D and outputs the input signals of the first parameter Q and the second parameter D as the estimated inductance L.

Further, the feedback controller optimal parameter decision device comprises K_{p_q}Table look-up module and K_{i_q}Table look-up module, K_{p_d}Table look-up module and K_{i_d}And a table look-up module. K_{p_q}The table look-up module inputs signals of the estimation resistance R and the estimation inductance L and outputs signals of the q-axis feedback control proportionality coefficient K_{p_q}。K_{i_q}The table look-up module inputs signals of the estimation resistance R and the estimation inductance L and outputs signals of the q-axis feedback control integral coefficient K_{i_q}。K_{p_d}The table look-up module inputs signals of the estimated resistance R and the estimated inductance L and outputs signals of the d-axis feedback control proportionality coefficient K_{p_d}。K_{i_d}The table look-up module inputs signals of the estimation resistance R and the estimation inductance L and outputs signals of the d-axis feedback control integral coefficient K_{i_d}。

Further, the voltage converter comprises a Park inverse transformation, SVPWM and an inverter,

the q-axis target voltage u_qAnd the d-axis target voltage u_dCarrying out Park inverse transformation by using the rotation angle theta to obtain alpha phase voltage u_αAnd beta phase voltage u_βAlpha phase voltage u_αAnd beta phase voltage u_βAnd obtaining the three-phase voltage of the permanent magnet synchronous motor through SVPWM and an inverter.

Further, the current transformer comprises a Clarke transform and a Park transform,

the three-phase current i_a、i_bAnd i_cObtaining alpha phase current i by Clarke transformation_αBeta phase current i_βThen, the alpha phase current i is converted into the alpha phase current by using the rotation angle theta_αBeta phase current i_βCarrying out Park conversion to obtain the q-axis actual current i_q ^*And d-axis actual current i_d ^*。

Further, the transfer function of the q-axis current feedback controller is:

further, the transfer function of the d-axis current feedback controller is:

compared with the prior art, the invention has the beneficial effects that:

the feedforward control structure and the design target provided by the invention can be used for optimally solving the parameters of the second-order current feedforward controller, and the parameters of the feedback controller can be obtained by using the resistance and inductance estimator provided by the invention through a table look-up module, namely the forward solving of the control parameters is realized. Compared with the existing current feedback control and bang-bang control effects, the current control effect of the invention has the advantages of improving the response speed of the current and reducing the fluctuation of the current.

Drawings

Fig. 1 is a structural diagram of a torque control device of a permanent magnet synchronous motor.

Fig. 2 is a block diagram of an equivalent control of a current feedforward controller.

Fig. 3 is a schematic diagram of a resistance and inductance estimator.

Fig. 4 is a schematic diagram of an optimal parameter decision device of the feedback controller.

FIG. 5 is a flow chart of the table lookup module value determination in the optimal parameter decision device of the feedback controller.

Fig. 6 is a time domain response diagram of the conventional pm synchronous motor torque control technique.

Fig. 7 is a time domain response diagram of the conventional permanent magnet synchronous motor torque control technology.

Fig. 8 is a time domain response diagram of the permanent magnet synchronous motor torque control of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer and clearer, the present invention is further described in detail below by referring to the accompanying drawings and examples.

Fig. 1 shows a structure of a torque control device for a permanent magnet synchronous motor. A permanent magnet synchronous motor torque control device includes: a current feedforward controller 101, the input signal of the current feedforward controller 101 is a target current signal i_cmdThe output signal is a q-axis target current i_q。

The device also comprises a q-axis current feedback controller 104 and a d-axis current feedback controller 105, wherein the q-axis current feedback controller 104 inputs a signal of the q-axis target current i_qAnd q-axis actual current i_q ^*Of q-axis target current i, summing module 1021_qAnd q-axis actual current i_q ^*The difference value is obtained by summing the values obtained by the inverse number module 103, and the output signal is a q-axis target voltage u_q. The d-axis current feedback controller 105 inputs a d-axis target current i_dAnd d-axis actual current i_d ^*The summation module 1022 sums the d-axis target current i_dAnd d-axis actual current i_d ^*The values obtained after the inverse number module 103 are summed to obtain a difference value, and the output signal is a d-axis target voltage u_d。

A resistance and inductance estimator 106, wherein the input signal of the resistance and inductance estimator 106 is the q-axis target current i_qQ-axis actual current i_q ^*The d-axis target current i_dAnd the d-axis actual current i_d ^*The output signals are the estimated resistance R and the inductance L.

A feedback controller optimal parameter decision-making unit 107, wherein the feedback controller optimal parameter decision-making unit 107 inputs the estimated resistance R and the inductance L as signals and outputs q-axis feedback as signalsControlling the proportionality coefficient K_{p_q}And q-axis feedback control integral coefficient K_{i_q}D-axis feedback control proportionality coefficient K_{p_d}And d-axis feedback control integral coefficient K_{i_d}. The transfer function of the q-axis current feedback controller 104 is controlled by the q-axis feedback to control the proportionality coefficient K_{p_q}And q-axis feedback control integral coefficient K_{i_q}Composition, q-axis feedback control proportionality coefficient K_{p_q}And q-axis feedback control integral coefficient K_{i_q}And functions to adjust the frequency transfer characteristics of the q-axis current feedback controller 104. The transfer function of the d-axis current feedback controller 105 is controlled by the d-axis feedback to control the proportionality coefficient K_{p_d}And d-axis feedback control integral coefficient K_{i_d}Composition, d-axis feedback control proportionality coefficient K_{p_d}And d-axis feedback control integral coefficient K_{i_d}And functions to adjust the frequency transfer characteristics of the d-axis current feedback controller 105.

And the position sensor 108 is used for measuring the rotor position of the permanent magnet synchronous motor 110, and the output signal is the rotation angle theta.

A voltage converter 109, wherein the voltage converter 109 inputs the q-axis target voltage u_qAnd the d-axis target voltage u_dAnd the output signal of the rotation angle theta is the three-phase voltage of the permanent magnet synchronous motor.

The permanent magnet synchronous motor 110, the input signal of the permanent magnet synchronous motor 110 is the three-phase voltage, and the output signal is the three-phase current i_a、i_bAnd i_c。

A current converter 111, the input signal of the current converter 111 is the three-phase current i_a、i_bAnd i_cThe output signal of the rotation angle theta is the actual current i of the q axis_q ^*And d-axis actual current i_d ^*。

A voltage converter 109 for converting the input signal q-axis target voltage u_qAnd the d-axis target voltage u_dPark inverse transformation 1091 is carried out by utilizing the rotation angle theta to obtain alpha phase voltage u_αBeta phase voltage u_βAlpha phase voltage u_αBeta phase voltage u_βAnd obtaining the three-phase voltage of the permanent magnet synchronous motor through the SVPWM1092 and the inverter 1093.

A current converter 111 for converting the input signal into three-phase current i_a、i_bAnd i_cAlpha phase current i is obtained by Clarke transformation 1112_αBeta phase current i_βThen, the alpha phase current i is converted into the alpha phase current by using the rotation angle theta_αBeta phase current i_βCarrying out Park conversion 1111 to obtain q-axis actual current i_q ^*And d-axis actual current i_d ^*。

According to the equivalent control block diagram of the current feedforward controller, as shown in fig. 2, the design target of the current feedforward controller is obtained as follows:

wherein Q is_ff(s) is the transfer function of the current feedforward controller, G_{I_eq}(s) is a q-axis target current i_qFor input and q-axis actual current i_q ^*Is the transfer function of the output permanent magnet synchronous motor. U(s) represents system input, D(s) represents disturbance, U_ff(s) represents feed forward output, Y(s) represents process output, Q_fb(s) stands for feedback controller, G_{I_real}(s) is a practical system.

The transfer function of the current feedforward controller 101 is:

where pole p₁And p₂Zero point z₁And z₂By optimizing the design objective.

The schematic diagram of the resistance and inductance estimator is shown in fig. 3. The resistance and inductance estimator 106 comprises a q-axis current lookup table module 1061, a d-axis current lookup table module 1062, a resistance lookup table module 1063 and an inductance lookup table module 1064, wherein the q-axis current lookup table module inputs a signal of the q-axis target current i_qWith said q-axis actual current i_q ^*The output signal is a parameter Q. The d-axis current look-up table module inputs a signal as the d-axis target current i_dAnd the d-axis actual current i_d ^*The output signal is a parameter D. The resistance look-up table module inputs signals of the parameter Q and the parameter D and outputs the parameters of the parameter Q and the parameter D as the estimated resistance R. The inductance look-up table module inputs signals of the parameter Q and the parameter D and outputs the input signals of the parameter Q and the parameter D as the estimated inductance L.

And measuring the mapping relation between the current of the permanent magnet synchronous motor and the resistance and the inductance in an off-line manner, and determining the numerical value of a table look-up module in the resistance and inductance estimator (the table look-up module is in a discrete expression form of the mapping relation between the current and the resistance and the inductance). The method comprises the following specific steps: and increasing the q-axis target current from the initial value to the final value according to a certain increment step, and simultaneously measuring the q-axis actual current, the resistance and the inductance to obtain the mapping relation between the q-axis current and the resistance and the inductance. And increasing the d-axis target current from the initial value to the final value according to a certain increment step, and measuring the actual current, the resistance and the inductance of the d-axis to obtain the mapping relation between the d-axis current and the resistance and the inductance. The mapping relation of the q-axis current and the resistance and the inductance is taken as a primary mapping relation, and the mapping relation of the d-axis current and the resistance and the inductance is taken as a secondary mapping relation. And the secondary mapping relation is used for correction on the basis of the primary mapping relation, and the values of the q-axis current lookup table module 1061, the d-axis current lookup table module 1062, the resistance lookup table module 1063 and the inductance lookup table module 1064 are finally determined.

The transfer function of the q-axis current feedback controller 104 is:

the transfer function of the d-axis current feedback controller 105 is:

the structure diagram of the optimal parameter decision device according to the feedback controller is shown in fig. 4. The feedback controller optimal parameter decision maker 107 comprises K_{p_q}Table lookup modules 1071 and K_{i_q}Table look-up module 1072, K_{p_d}Table lookup modules 1073 and K_{i_d}Table checking moduleBlock 1074. K_{p_q}The table look-up module 1071 inputs the signal into the estimation resistance R and the estimation inductance L and outputs the signal into the q-axis feedback control proportionality coefficient K_{p_q}。K_{i_q}The table look-up module 1072 inputs the signal into the estimation resistance R and the estimation inductance L and outputs the signal into the q-axis feedback control integral coefficient K_{i_q}。K_{p_d}The table look-up module 1073 inputs the signals of the estimated resistance R and the estimated inductance L and outputs the signals of the d-axis feedback control proportionality coefficient K_{p_d}。K_{i_d}The table look-up module 1074 inputs the signal into the estimation resistance R and the estimation inductance L and outputs the signal into the d-axis feedback control integral coefficient K_{i_d}。

The change of motor parameters can influence the current control effect of the motor, the change of the resistance and the inductance of the motor can influence the system performance, the current is easy to generate larger fluctuation, and then the motor is easy to generate larger torque fluctuation. Determining a flow chart according to the numerical value of a table look-up module in the optimal parameter decision device of the feedback controller, as shown in fig. 5, firstly setting initial values, increment steps and final values of the resistance and the inductance, increasing the resistance and the inductance from the initial values to the final values according to the increment steps to obtain a group of different resistance and inductance parameters, calculating the optimal PI parameters of the motor under different resistances and different inductances by adopting a genetic algorithm, and forming a two-dimensional number table by using the resistance, the inductance and the optimal PI parameters. Finally, the table look-up module value in the optimal parameter decision device 107 of the feedback controller is determined.

K_{p_q}、K_{i_q}、K_{p_d}And K_{i_d}Can be represented by the following mapping relationship.

K_{p_q}＝f₁(R,L)

K_{i_q}＝f₂(R,L)

K_{p_d}＝f₃(R,L)

K_{i_d}＝f₄(R,L)

The current feedforward controller 101 is used to reduce the current disturbance of the permanent magnet synchronous motor and improve the response speed of the motor. And the q-axis current feedback controller 104 and the d-axis current feedback controller 105 are used for current feedback control of the permanent magnet synchronous motor, reducing the steady-state error of the motor and improving the stability and the robustness of the motor. The current feedforward controller 101 transfer function adopts a second-order structure and a resistor, and the inductance estimator 106 and the feedback controller optimal parameter decision maker 107 adopt a table look-up module, so that the embedded realization is easy.

Fig. 6 to 8 are a time domain response diagram of the conventional permanent magnet synchronous motor torque control technique, and a time domain response diagram of the permanent magnet synchronous motor torque control of the present invention. It can be seen from the figure that the difference between the target current and the actual current is large in the existing technology for controlling the torque of the permanent magnet synchronous motor, while the actual current under the control of the torque control device of the permanent magnet synchronous motor of the invention closely follows the target current, the actual current follows the target current within 0.01 second, and the fluctuation of the actual current is within 0.5 ampere, therefore, the control device of the embodiment can effectively inhibit the torque fluctuation of the permanent magnet synchronous motor, and the permanent magnet synchronous motor is correspondingly rapid.

The present invention has been illustrated by the foregoing examples, but it should be understood that the foregoing examples are for purposes of illustration and description only and are not intended to limit the invention to the scope of the examples described. Furthermore, it will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that many variations and modifications may be made in accordance with the teachings of the present invention, all of which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.