Research On Fault Tolerance Control Of Permanent Magnet Vernier Motor Driven By Vector Control

The intensification of environmental pollution and the impact of energy crisis continue to drive the industrial design of electric motors and their control technologies towards high efficiency and energy saving.As a new type of AC motor,the permanent magnet synchronous motor has the advantages of simple structure,reliable operation,small size and light weight,high efficiency and high power density,etc.It has been obtained in various fields such as elevators,ship power propulsion,automobiles,and industrial automation.As an important execution component,the high performance and high reliability of the motor drive system are directly related to the safe operation of the entire system.The fault-tolerant motor drive system has become a research hotspot in recent years because it can guarantee the safe operation of the entire system without loss of performance or partial degradation of performance.In this paper,a permanent magnet vernier motor based on“magnetic gear effect”is mainly used as a control object.Based on the study of motor vector control,a fault-tolerant control strategy for motor drive system is proposed for common inverter power device faults in motor drive systems.The in-depth theoretical,simulation and experimental analysis are carried out to verify the correctness of the theoretical analysis.All of the main research contents of the paper are listed below:1.The mathematical model of the permanent magnet vernier motor was established,and the voltage equation,flux linkage equation,torque equation and motion equation of the permanent magnet vernier motor in different coordinate systems were deduced.The coordinate transformation equations commonly used in permanent magnet motor control are deduced and the coordinate transformation matrix between different coordinate systems is obtained.2.The principle of the vector control principle of the permanent magnet vernier motor and the typical pulse width modulation strategy are discussed.This paper introduced several typical ector control implementation strategies and used i_d=0 control as an example to construct a ector control system based on CHBPWM and a vector control system based on SVPWM, which provides a theoretical basis for the establishment of a simulation model.3.The topology reconstruction scheme of the motor drive system and its operational principle are analyzed under the fault condition of one-phase bridge-arm of the inverter.The spatial voltage vector distribution of the inverter after fault reconstruction is analyzed.The modulation strategy and detailed implementation steps of the space voltage vector of the four-switch inverter are discussed.Based on this,a four-switch fault-tolerant strategy vector control system is constructed,which provides a theoretical basis for the establishment of the simulation model.4.The MATLAB/Simulink modeling tool is used to build the vector control model under the normal condition of the inverter and the four-switch fault-tolerant control simulation model after the failure of the one-phase bridge arm of the inverter.The proposed control strategy was verified by simulation.Finally,the experimental results demonstrated the correctness of the simulation.