Research On Model Predictive Current Control Of Induction Motor Model Based On Vector Control

With the continuous development and progress of science and technology,AC drive control system has become the main direction of development of electrical drive control.The research and development of high-performance AC variable frequency speed control technology is of great significance to realize “Created in China” and “Intelligent manufacturing in China”.In recent years,a high-performance control strategy called model predictive control has been applied in the field of power electronics,attracted a wide range of concerns around the world by virtue of its simple structure,strong applicability,multi-objective,easy handling of constraints,and so on.In this paper,taking the induction motor speed control system as the research object,basing on the traditional vector control method,the model predictive current control technology has been deeply studiedAt first,this paper introduces the basic principle of model predictive current control in detail.In order to analyze and explain the control performance of the predictive controller,this paper designs a model predictive current control system of three-phase two-level voltage source inverter with resistance inductance model of back electromotive force as a load,including the design of discrete system model,predictive controller,cost function and so on.Through the simulation analysis of the design of the control system,a detailed analysis shows the control delay,reference value,model accuracy and other factors on the control performance,and gives an improvement plan.At the same time,compared with the conventional PI control SVPWM modulation control system,the control performance of the system is analyzed.In addition,taking into account the actual situation in the power converter switching frequency of the factors,this paper presents two methods to improve the average switching frequency of the current control system,cost function method and boundary circle strategy.Considering the computational limit of the algorithm in actual situation,the paper proposes an improved boundary circle strategy,which can effectively reduce the average switching frequency of the predictive control system under the premise of ensuring the control performance.The simulation results verify the feasibility of the improved scheme.Then,this paper introduces the basic idea of the model predictive current control of induction motor based on the traditional vector control method,and designs the control system.Firstly,a discrete time model of induction motor with sufficient precision is designed.Then,a full-order closed-loop rotor flux observer is designed in order to exert the respective advantages of voltage and current model.The speed controller,flux regulator and so on of the control system is designed also.Finally,the simulation of the designed induction motor control system is carried out to contrast the control performance between flux-open-loop system and flux-closed-loopsystem.The study shows that the model predictive current control system of flux-closed-loop system has better response speed and dynamic performance.In this paper,the induction motor model current control algorithm with improved boundary circle strategy is designed,and the simulation analysis is carried out to further verify the feasibility of the improvement strategy.