Research On Control Technology To Tolerate The Single Phase Fault Of Permanent Magnet DC Motor

Now, the applications of permanent magnetic DC motor in industrial production, agricultural production, military equipment and aerospace are growing very fast every day. It is becoming more and more important to ensure operation of the motor safe and stable. When the motor or controller failure occurs,it will greatly reduce the losses of economy and society to find some ways to guarantee the motor running. This has an important value for some special industries.According to single-phase bridge arm fault and single phase inter-turn short circuit fault, the follow works are studied: the main circuit of the motor controller under the normal condition and fault condition has been analyzed. The control strategy of switching devices and the calculation of the switching time are studied under the fault tolerance condition based on SVPWM theory. The calculation method of circuit switching time is given under the fault tolerance condition. The characteristics of the controller for a single phase bridge arm fault and single-phase fault of inter-turn short circuit are studied. Fault detection and fault judgment are realized. It provides the basis to turn off the fault part fastly and accurately, and make the fault tolerance circuit put into use.The simulation is carried out for the controller circuit in the normal situation, the single-phase bridge arm fault and single-phase winding inter-turn short circuit fault by ANSOFT. Compared with the normal condition, the torque ripple under fault condition will be increased and the torque will be reduced. The controller circuit can not ensure the normal work of the motor any more. For single phase bridge arm of failure, the fault tolerant circuit of four legs three-phase and four switch three-phase are simulated by ANSOFT. For the single phase winding inter-turn short circuit fault, the fault tolerant circuit of four legs two-phase and the four switchs two-phase are simulated. The simulation study makes the motor continue to work in some special circumstance.Simulation results show that the motor torque fluctuation is significantly reduced by fault tolerant controller. The motor torque approximate return to normal value under the fault tolerant control strategy of four legs three-phase and four switch three-phase. The motor torque is restored to 1 3 times of normal torque by the four legs two-phase and the four switch two-phase tolerant controller.On conclusion, the corresponding optimal control strategy is four switch three-phase control circuit and four switch two-phase control circuit under the fault of the single-phase bridge and single-phase inter-turn short circuit repectively.