Research On Fault Analysis And Fault Tolerant Control Technology Of Wheel Motor For Electric Vehicle

The brushless DC motor is mostly used as the hub motor of distributed-driving electric vehicles; and due to poor operating environment, the variety faults of brushless DC motor would occur; especially the single-phase winding-broken fault(SPWBF) is the most common. The SPWBF will cause the asymmetrical three-phase currents, and acute torque ripple, and the great speed fluctuation. Therefore, in this paper, the SPWBF is studied as a main problem. Firstly, the mechanisms of the motor working under SPWBF are analyzed in detail, and then a fault-tolerant control scheme called two-phase four-state is proposed. Secondly, by comparison of the mechanism of the two operations, i.e. normal three-phase sis-state and the two-phase four-state, it is found that the motor in two-phase four-state operation mode would generate the asymmetry of the three-phase current, the fluctuating of transferring torque and the decline of average torque. For this reason, thirdly, a control algorithm of hybrid non-singular terminal sliding mode is adopted to optimize and compensate the control system of the motor when the fault occurs. Finally, the simulations of MATLAB and experiments based on the TI DSP system TMS320F2812 are worded out, the results show that the torque ripple can be reduced and the motor can run smoothly in the failure by the control algorithm.