阅读说明：本技术 一种基于终端滑模的永磁同步电机矢量控制方法 (Permanent magnet synchronous motor vector control method based on terminal sliding mode ) 是由 侯勇 方云 游国栋 于 2020-06-09 设计创作，主要内容包括：本发明属于永磁同步电机控制技术领域,涉及了一种基于终端滑模的永磁同步电机矢量控制方法,其主要特点是：在传统的永磁同步电机磁场定向控制策略基础上,针对速度控制环,设计了一种基于终端滑模的控制器,实现系统速度的快速准确跟踪控制,并且,根据永磁同步电机在转速同步旋转坐标系统下的状态模型,将q轴电流的控制整合到速度控制环节中,实现转速和q轴电流的一次性综合控制,仅对d轴电流实施独立控制,从而使控制过程得以简化。与传统PID控制方法相比,本发明设计的控制策略具有转速调节响应速度快、无超调、精度高、稳定性好等优点。为永磁同步电机的控制提供了一种新思路,具有良好的工程应用前景。(The invention belongs to the technical field of permanent magnet synchronous motor control, and relates to a permanent magnet synchronous motor vector control method based on a terminal sliding mode, which is mainly characterized by comprising the following steps: on the basis of a traditional permanent magnet synchronous motor magnetic field directional control strategy, a controller based on a terminal sliding mode is designed for a speed control loop, so that the rapid and accurate tracking control of the system speed is realized, in addition, the control of the q-axis current is integrated into a speed control link according to a state model of the permanent magnet synchronous motor under a rotating speed synchronous rotating coordinate system, the one-time comprehensive control of the rotating speed and the q-axis current is realized, and only the d-axis current is independently controlled, so that the control process is simplified. Compared with the traditional PID control method, the control strategy designed by the invention has the advantages of high speed regulation response speed, no overshoot, high precision, good stability and the like. Provides a new idea for the control of the permanent magnet synchronous motor and has good engineering application prospect.)

1. A permanent magnet synchronous motor vector control method based on terminal sliding mode control is characterized by comprising the following steps:

(1) establishing a mathematical model of a Permanent Magnet Synchronous Motor (PMSM) under dq, wherein the mathematical model of the PMSM is expressed as follows:

for the surface PMSM, Ld ═ Lq ═ L, the torque equation is:

the equation of motion is:

in the formula u_d、u_qThe voltages of d and q axes of the stator are respectively; i.e. i_d、i_qD-axis current and q-axis current of the stator respectively; l is_d、L_qThe inductors of the d axis and the q axis of the stator are respectively; r is a stator resistor; Ψ_fIs a permanent magnet flux linkage; omega is the rotor electrical angular velocity; t is_e，T_LElectromagnetic torque and load torque respectively; j is moment of inertia; n is_pThe number of pole pairs of the motor is shown.

(2) Permanent magnet synchronous motor controller design based on Terminal Sliding Mode (TSM)

Selecting the PMSM speed deviation as a system state variable, namely:

selecting a terminal sliding mode surface as follows:

wherein: beta is more than 0, p and q are positive odd numbers, and q/p is more than 0 and less than 1

In order to reduce buffeting in sliding mode control, a sliding mode control mode of an index approach law is selected, namely:

from the formula (6)

From the formulae (2) and (3)

The combined type (1), (5), (6) and (7) can be obtained by neglecting the influence of instantaneous sudden change of the speed reference value and load torque disturbance

The formula (8) is a terminal sliding mode controller formula of the speed ring, the formula not only realizes the tracking control of the system rotating speed, but also comprises the stator q-axis current control in the traditional vector control strategy, namely the q-axis instruction voltage of the system is directly obtained through the speed controller.

In the invention, the control of the d-axis current still adopts the traditional PI controller.

In the invention, the terminal sliding mode surface function in the step (2) can make the state of the system converge to zero within a limited time, overcomes the defect of gradual convergence of the state under the linear sliding mode surface, optimizes the dynamic performance of the system, and has the advantages of high corresponding speed, high stable tracking precision and the like.

Technical Field

The invention relates to a control method of a permanent magnet synchronous motor, in particular to a control method based on a terminal sliding mode technology and a permanent magnet synchronous motor magnetic field orientation control technology.

Background

In a traditional vector control method of a permanent magnet synchronous motor, a PI controller is usually adopted to realize tracking control of rotating speed and current. The permanent magnet synchronous motor is a typical multivariable, strong-coupling and nonlinear system, although PI control is simple and easy to implement and can meet the control requirements of the system to a certain extent, the dependence on a system model is strong, when the system is disturbed externally or perturbed by parameters, the high-precision control effect is difficult to achieve, and the robustness of the system is poor. The sliding mode variable structure control has low requirements on the precision of a system mathematical model, has strong robustness on perturbation of system parameters and external disturbance, and is largely applied to the control of the permanent magnet synchronous motor. A common sliding mode variable structure control method adopts a linear sliding mode surface function, the state of a system reaches a balance point after infinite time, and buffeting exists in the controlled variable.

Disclosure of Invention

Aiming at the problems of poor robustness of a traditional permanent magnet synchronous motor vector control strategy based on a PI controller and infinite balance time of a linear sliding mode surface system, a permanent magnet synchronous motor vector control method based on terminal sliding mode control is provided.

In order to achieve the purpose, the technical scheme adopted by the invention for solving the technical problem is as follows:

a permanent magnet synchronous motor vector control method based on terminal sliding mode control comprises the following steps:

(1) establishing a mathematical model of a Permanent Magnet Synchronous Motor (PMSM) under dq, wherein the mathematical model of the PMSM is expressed as follows:

for the surface PMSM, Ld ═ Lq ═ L, the torque equation is:

the equation of motion is:

in the formula u_d、u_qThe voltages of d and q axes of the stator are respectively;i_d、i_qd-axis current and q-axis current of the stator respectively; l is_d、L_qThe inductors of the d axis and the q axis of the stator are respectively; r is a stator resistor; Ψ_fIs a permanent magnet flux linkage; omega is the rotor electrical angular velocity; t is_e，T_LElectromagnetic torque and load torque respectively; j is moment of inertia; n is_pThe number of pole pairs of the motor is shown.

(2) Permanent magnet synchronous motor controller design based on Terminal Sliding Mode (TSM)

Selecting the PMSM speed deviation as a system state variable, namely:

selecting a terminal sliding mode surface as follows:

wherein: beta is more than 0, p and q are positive odd numbers, and q/p is more than 0 and less than 1

In order to reduce buffeting in sliding mode control, a sliding mode control mode of an index approach law is selected, namely:

from the formula (6)

From the formulae (2) and (3)

The combined type (1), (5), (6) and (7) can be obtained by neglecting the influence of instantaneous sudden change of the speed reference value and load torque disturbance

The formula (8) is a terminal sliding mode controller formula of the speed ring, the formula not only realizes the tracking control of the system rotating speed, but also comprises the stator q-axis current control in the traditional vector control strategy, namely the q-axis instruction voltage of the system is directly obtained through the speed controller.

In the invention, the control of the d-axis current still adopts the traditional PI controller.

In the invention, the terminal sliding mode surface function in the step (2) can make the state of the system converge to zero within a limited time, overcomes the defect of gradual convergence of the state under the linear sliding mode surface, optimizes the dynamic performance of the system, and has the advantages of high corresponding speed, high stable tracking precision and the like.

The vector control method for the permanent magnet synchronous motor based on the terminal sliding mode is characterized in that a controller based on the terminal sliding mode is designed aiming at a speed control loop on the basis of a traditional permanent magnet synchronous motor magnetic field directional control strategy, so that the rapid and accurate tracking control of the system speed is realized, in addition, the control of the q-axis current is integrated into a speed control link according to a state model of the permanent magnet synchronous motor under a rotating speed synchronous rotating coordinate system, the one-time comprehensive control of the rotating speed and the q-axis current is realized, and only the d-axis current is independently controlled, so that the control process is simplified. Compared with the traditional PI control method, the control method provided by the invention has the advantages of high speed regulation response speed, no overshoot, high precision, good robustness to torque sudden change and good system stability.

Drawings

FIG. 1: control system schematic diagram of the invention

Detailed Description

The following describes a permanent magnet synchronous motor vector control method based on a terminal sliding mode in detail with reference to the accompanying drawings and embodiments.

Fig. 1 is a system schematic diagram of a permanent magnet synchronous motor vector control method based on a terminal sliding mode according to the present invention. The vector control method of the permanent magnet synchronous motor based on the terminal sliding mode is described by combining with fig. 1, and comprises the following steps:

(1) establishing a mathematical model of a Permanent Magnet Synchronous Motor (PMSM) under dq, wherein the mathematical model of the PMSM is expressed as follows:

for the surface PMSM, Ld ═ Lq ═ L, the torque equation is:

the equation of motion is:

in the formula u_d、u_qThe voltages of d and q axes of the stator are respectively; i.e. i_d、i_qD-axis current and q-axis current of the stator respectively; l is_d、L_qThe inductors of the d axis and the q axis of the stator are respectively; r is a stator resistor; Ψ_fIs a permanent magnet flux linkage; omega is the rotor electrical angular velocity; t is_e，T_LElectromagnetic torque and load torque respectively; j is moment of inertia; n is_pThe number of pole pairs of the motor is shown.

(2) Permanent magnet synchronous motor controller design based on terminal sliding mode

Selecting the PMSM speed deviation as a system state variable, namely:

selecting a terminal sliding mode surface as follows:

wherein: beta is more than 0, p and q are positive odd numbers, and q/p is more than 0 and less than 1

In order to reduce buffeting in sliding mode control, a sliding mode control mode of an index approach law is selected, namely:

from the formula (6)

From the formulae (2) and (3)

The combined type (1), (5), (6) and (7) can be obtained by neglecting the influence of instantaneous sudden change of the speed reference value and load torque disturbance

The formula (8) is a terminal sliding mode controller formula of the speed ring, the formula not only realizes the tracking control of the system rotating speed, but also comprises the stator q-axis current control in the traditional vector control strategy, namely the q-axis instruction voltage of the system is directly obtained through the speed controller.

In the invention, the control of the d-axis current still adopts the traditional PI controller.

In the invention, the terminal sliding mode surface function in the step (2) can make the state of the system converge to zero within a limited time, overcomes the defect of gradual convergence of the state under the linear sliding mode surface, optimizes the dynamic performance of the system, and has the advantages of high corresponding speed, high stable tracking precision and the like.