Fault Analysis And Fault Tolerant Control Of Switched Reluctance Motor Drive Inverter For Electric Vehicles

Switched reluctance motor speed control system has become a strong competitor in the new generation of speed control system because of its simple and robust structure,flexible and controllable parameters,and excellent fault tolerance and other characteristics.As the core of energy conversion in this system,power converter is the weakest link that is most prone to failure,often manifested as short-circuit fault and open-circuit fault.In view of this,this paper aims to improve the performance and reliability of the switched reluctance motor system,and analyzes and studies the fault tolerance of the power converter.In this paper,a three-phase asymmetric half-bridge power converter based on a 12/8 switched reluctance motor is used as the research object.The short-circuit fault and open-circuit fault of the power switches are analyzed respectively,and the corresponding fault-tolerant control methods are proposed.For the short-circuit fault of the power switches,firstly,the faulty characteristics of the power switches under short-circuit are analyzed.The linear model of the switched reluctance motor system is used to analyze the internal causes of the short-circuit fault current overshoot and the system torque ripple.Then,a fault-tolerant control method of variable conduction angle with adjustable duty cycle based on derating under different working conditions is proposed.Finally,the Matlab/Simulink simulation model and the RT-LAB hardware-in-the-loop simulation platform are built respectively.These simulation and experimental results are presented to confirm the correctness and effectiveness of the proposed short-circuit fault-tolerant control strategy.For the open-circuit fault of the power switches,firstly,the change of the working mode of the faulty circuit under the open-circuit fault of the power switches is analyzed,and then the H-bridge structure widely used in the engineering is applied as the fault-tolerant control topology when the open-circuit fault of power switch(es)occurs.Besides,the corresponding multi-directional current soft chopping control method is proposed.Finally,the Matlab/Simulink simulation model and the dSPACE hardware-in-the-loop simulation platform are built respectively.These simulation and experimental results are presented to confirm the feasibility and practicability of the proposed short-circuit fault-tolerant control strategy.