Faulted behaviour of permanent magnet electric vehicle traction drives

The paper considers the implications of typical faults on the design and operation of permanent magnet (PM) traction drives. As the excitation of these machines is fixed, it is not sufficient to simply disconnect the machine by gating off the inverter power semiconductors following the detection of a fault, and other remedial actions need to be employed. A range of single point winding and power semiconductor failures are analysed in detail and for each the most appropriate mitigating action described. The discussion is illustrated with test results taken from two identically rated salient and nonsalient PM traction motors.