Research On PMSM Control System Driven By Z-source Inverter

Permanent magnet synchronous motor(PMSM)is widely used in industry and daily life because of its superior performance.The output voltage of the rectifier-inverter two-stage circuit used in the original drive circuit of PMSM is always lower than the input voltage.In order to realize the boost function,the direct current(DC)boost circuit needs to be added,which leads to the complexity of the drive circuit structure and the increase of the cost.As a new type of inverters,Z-source inverters can realize the functions of boost and inversion at the same time only with one-stage circuit structure,unlike traditional drive circuits which require two-stage circuits.The circuit structure of Z-source inverter is especially suitable for low input voltage and large voltage fluctuation.This paper takes the drive system composed of Z-source inverter and permanent magnet synchronous motor as the research object.The circuit structure and working principle are analyzed,and the control algorithm is designed.The effectiveness of the PMSM control system based on Z-source inverters is verified by simulation experiments.Firstly,the research significance of this topic is clarified and the research status of Zsource inverter and PMSM drive system at home and abroad is summarized.The realization method of shoot-through vector of Z-source inverter is studied.The pulse width modulation(PWM)strategy of Z-source inverter is obtained via the analysis of SVPWM modulation strategy.Secondly,the circuit structure and working principle of traditional Z-source inverters are introduced,and the Euler-Lagrange model of PMSM drive and control system based on traditional Z-source inverters is established in dq coordinate system.The motor speed controller is designed according to the passive control method based on energy.A load torque observer is designed to improve the dynamic and static performance of the system when the load is unknown.Thirdly,in order to solve the coupling problem of boost factor and modulation factor in traditional Z-source inverters,the isolated shoot-through Z-source inverters are introduced into PMSM drive system.This new drive system solves the shortcomings of the traditional Z-source inverter PMSM drive system,and simplifies the difficulty of system modeling and controller design.According to the circuit structure and working principle of the driving system,the DC-link voltage controller and PMSM speed controller of the separated Zsource inverter are designed respectively.Fourthly,the simulation analysis of PMSM control system based on traditional Z-source inverters and PMSM control system based on isolated shoot-through Z-source inverter is carried out on Matlab/Simulink simulation software,which verifies the feasibility of the control method.In this paper,the circuit structure and control method of PMSM control system based on Z-source inverters are studied.The simulation results show that the proposed method is reasonable and effective.The drive system based on Z-source inverter improves the performance of PMSM drive system.It is a promotion and improvement of the traditional PMSM drive and control system,and has good research and application value.