Pure Electric Vehicles Induction Motor Drive System Inverter Fault-tolerant Technology Research

Faced with the increasingly serious energy crisis and environmental pollution, thedevelopment of EV (electric vehicle) has drawn more and more attention. The motordrive system is the most important component of EV, its reliability will directly affectthe performance of the vehicle and traffic safety.As research indicated, the powerelectronic devices and the drive circuit of the motor drive system is the most frequentlink failure.The EV will lose power for the inverter failure, which may result in seriousimpact. Therefore it is necessary to research fault tolerance for the inverter of EV’smotor drive system. The three-phase four-switch running mode is introduced to acquirefault-tolerant running on the basis of better performance and lower cost. An in-depthresearch for the three-phase four-switch fault-tolerant control of EV’s motor driv systemhas been done in this article.First of all, The vector control technology has been introduced based on themathematical model of asynchronous motor, then the vector control principles andSpace Vector Pulse Width Modulation(SVPWM) have been analyzed.the fault-tolerantcontrol method with three-phase four-switch inverter for motor drive inverter ofasynchronous motor has been proposed to solve failure of the motor drive system. And adetailed research of its operating principle and Space Vector Pulse WidthModulation(SVPWM) has been done. After a depth analysis of Maximum torque outputin the three-phase four-switch operation mode, the probability of the battery voltage andso on, the matter of EV that need to be paid attention on the tolerance mode has beengiven. A voltage compensation method has been proposed to ensure the stable operationof the system for the imbalance of the three-phase four-switch running in the DC buscapacitors.Secondly, building the various sub-modules to achieve the functions andfault-tolerant topology reconstruction module.The fault-tolerant control system hasbeen simulated by the Matlab/Simulink, and simulation results are given. And thesimulation results verify the feasibility of fault-tolerant control system and verify the conclusions of the analysis of fault-tolerant operating characteristics.Finally,the overall structure of EV’s motor drive system fault-tolerant control hasbeen designsd. The control system hardware, software modules. three-phase four-switchfault-tolerant control system experiments have been completed based on theexperimental platform with the1.1kw three-phase asynchronous motor. Theexperimental results show that the fault-tolerant control system can achieve faulttolerance, and the motor current has been improved to ensure the stability of the systemoperation and system reliability.