Research On Control Strategy Of Back-to-Back Converter Based On Permanent Magnet Synchronous Motor

With the advancement of technology and the development of motor control technology,the Back-to-Back converter with IGBT as the main component has the advantages of high power factor,compact DC side,energy bidirectional flow,etc,has been widely used in the AC motor speed control system.This paper focuses on the control strategy of the back-to-back converter system based on permanent magnet synchronous motor.In this paper,the basic principle of PWM rectifier is studied firstly.In order to solve the problem of steady-state error of power inner loop in traditional predictive power control of P WM rectifier,the direct power control method based on internal model principle is studied.Secondly,the motor model and control principle of permanent magnet synchronous motor are studied,and the current prediction control algorithm of permanent magnet synchronous motor is derived.Finally,the coordinated control strategy of power feedforward compensation in back-to-back converters is studied to improve the DC bus voltage fluctuation caused by sudden load changes during the traditional network side and machine side independent control,and improve the system's anti-load disturbance capability.Based on the above theory,this project builds a simulation model in MATLAB/Simulink.The PWM rectifier and back-to-back converter system are simulated respectively.And a two-level back-to-back power electronic converter platform with TMS320F28069 as the controller was built.Based on the experimental platform,the above theoretical research has been experimentally verified.The simulation and experimental results show that compared with the traditional predictive direct power control,the predictive direct power control based on the internal model principle reduces the steady-state error of the power inner loop.Compared with the traditional grid side and motor side independent control,the load power feedforward control system effectively reduces the DC side bus voltage fluctuation when the load changes.