Control method and system for permanent magnet synchronous motor based on current prediction

Abstract

The invention discloses a control method for a permanent magnet synchronous motor based on current prediction and belongs to the field of control over permanent magnet synchronous motors. The method mainly comprises the steps of predicting the improved current and identifying the sensorless rotating speed and a corner based on a phase-locked ring idea combined with the predicting step. According to the control method, the current of a motor stator is predicted ahead of a switch period according to the detected current of the motor stator and a current instruction; corresponding control voltage is predicted; and motor rotating speed and corner position information is identified according to the estimated counter electromotive force of the motor. The invention further provides a control system for realizing the control method. The control system comprises a rotating speed regulator, a current predicting unit, a counter electromotive force estimation unit, a controller and a space vector modulating unit. According to the control method and the control system disclosed by the invention, the permanent magnet synchronous motor can be enabled to still safely operate at high efficiency when the parameters change; and the control method and the control system have a favorable application prospect in the field of control over the permanent magnet synchronous motor.

Description

Technical field [0001] The present invention relates to a permanent magnet synchronous motor control strategy, and in particular to a permanent magnet synchronous motor control method based on phase-locked loop (PLL) sensorless and current prediction. Background technique [0002] Direct-drive permanent magnet wind turbines have many advantages over doubly-fed wind turbines in terms of operating efficiency, reliability, grid-connected control, fault ride-through, etc. In addition, the price of permanent magnet materials has dropped in recent years, making them rapidly become a variable speed constant frequency wind turbine. An important development direction in the field of wind power generation. In a direct-drive wind power generation system, the motor-side converter realizes energy conversion between wind energy and electric energy by controlling the rotation speed of the generator. However, the wind has the characteristics of "coming in and out and changing at any time". ...

AI Technical Summary

Problems solved by technology

[0003] Given that the predictive control algorithm combined with space vector modulation (SVPWM) technology has the advantages of fast and accurate control of current, constant switching frequency and low current ripple, and is suitable for digital implementation, some researchers refer to this method for permanent control. In the control system of magnetic synchronous motor, the predictive control algorithm is essentially a model-based control algorithm, which is sensitive to the mismatch of motor model parameters, and the motor has the characteristics that it is not suitable to know the precise parameters and the parameters are easy to change during operation. , so it is urgent to solve the problem of poor robustness of predictive control algorithm parameters

[0004] In order to achieve the purpose of motor control, it is necessary to know the speed and angle information of the motor in real time during the operation of the motor. However, traditional mechanical encoders have problems such as installation difficulties, encoders are easily affected by environmental factors, and have poor reliability. Therefore, in recent years, The rapid development of sensorless technology

However, due to the differences in the electrical characteristics of different motors and different control methods, the sensorless technology does not have universal applicability.

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