Research On Current Model Predictive Control Of Induction Machine

There are so many advantages of model predictive control algorithm such as high stability,flexibility and simplicity of the algorithm,swiftness of the dynamic response,easiness to deal with nonlinear constraints.The MPC is considered to be a new generation of high-performance control strategy after the vector control and direct torque control in the field of power electronics and motor control.Based on the field-oriented control theory and MPC method,the thesis took the induction motor as research objection,introduced MPC method and then conducted a relatively deep research on the control principle and control performance of current model predictive control of induction motor.The current model predictive control strategy of induction motor has been designed and completed in the thesis,and at the same time,the feasibility and effectiveness of the control strategy have been verified through the simulation and experiment.Then,this thesis introduces the basic principle of model prediction and points out three basic steps of predictive control.According to the mathematical models and state equations of asynchronous motor,the current prediction model in rotating coordinate system is established.Based on the magnetic field orientation strategy,the basic framework of current model predictive control is constructed.For the research on flux observer,some improvement measures of the discrete filters have been put forward in the thesis according to the error analysis of the voltage-model rotor flux observer.And by setting the appropriate cut-off frequency and compensation measures,the integral saturation and DC bias are eliminated.Based on the control processing of single-step current model predictive control,the linear fitting of future trajectory of the current is adapted to solve the problem of divergence and shock caused by current model predictive control algorithm.In view of a beat delay problem existing in the predictive control,this thesis puts forward a beat delay compensation strategy,which decreases the adverse effect caused by a beat delay problems.Aiming at the problem of high average switching frequency in the predictive control,the double border round strategy is introduced.Considering larger current error of the predictive control under lower sampling frequency,error prediction strategy is adopted to maintain current error under error limits effectively.In view of the high sampling frequency in predictive control,the theory of double-vector current model predictive control is introduced.The thesis introduces the simulation results of current model predictive control.The simulation results assess the dynamic response speed of asynchronous motor under the control of MPC and verify the correctness of the theoretical foundation of the current model predict control.The effect of the improvement strategy is compared and the correctness of different control algorithms is verified.Also,the control effect of the single-vector and double-vector current model predictive control is compared.The software platform and hardware platform of current model predictive control of induction machine are established,the experiment proved the validity of the control strategy.