Winding Short Circuits in the Switched Reluctance Drive

The switched reluctance drive is known to be fault tolerant, but it is not fault free. This paper takes an in-depth look at winding short circuits in this particular machine. Modeling and testing complement a theoretical analysis. Two cases need to be distinguished, one where a complete pole is shorted, and one where a few turns are shorted. Pole short circuits lead to torque reduction that can be easily compensated for with increased current. With few turns shorted, the impact on overall torque may actually be negligible, however, significant currents may circulate through the shorted turns, the worst case being with a single turn shorted with a zero resistance. These results are discussed with a view toward possible remediation schemes aside from simply turning off the faulted phase.