Research On Error Compensation Strategy Of Permanent Magnet Synchronous Motor Based On Model Prediction Control

Permanent magnet synchronous motors have been widely used in aerospace,transportation and other fields due to their advantages like high efficiency and highpower density.Model predictive control technology has great advantages in motor control because it can effectively handle multiple-input multiple-output and nonlinear systems.Model predictive control relies on the prediction model of the motor.However,when the working conditions change the motor parameters are affected and the predictive model is mismatched.Model mismatch can reduce the prediction accuracy and control performance.The thesis studies the current prediction error compensation algorithm based on model predictive control for the permanent magnet synchronous motor.First of all,this thesis takes the changes of resistance,permanent magnet flux linkage and inductance as the main disturbance factors in view of the problem of predicted current error caused by model mismatch.The prediction error formula is deduced when parameter changes to analyzes the affect of parameters changes on the predicted current error and the impact on the stability of the control system.Simulation model is built in software to verify the validity of the theoretical analysis,which lays a foundation for the study of the prediction current error compensation algorithm.Secondly,an improved prediction current error compensation strategy is proposed according to the parameter mismatch information contained in the current error.In the calculation of the predicted current,the predictive current can be compensated by the previous current error of the corresponding voltage vector according to the characteristics of error information contained in the predicted current error.In the evaluation of value function,the information of parameter disturbance in the steady state is introduced through the prediction error cumulant with the piecewise function to overcome the problem that the disturbance of resistance and permanent magnet flux linkage is ignored in the traditional compensation strategy.The voltage vector that can weaken the affect of parameter disturbance is selected to improve the robustness of the control system.The simulation model is established on the MATLAB platform to verify the effectiveness of the algorithm proposed in this thesis.Finally,a permanent magnet synchronous motor experimental platform is built based on TMS320F28335.The actual effect of the proposed compensation algorithm for predicted current error is tested.The experimental results show that the compensation algorithm can effectively reduce the predicted current error.