Fault tolerant power converter for switched reluctance drives

One of the main features of a switched reluctance motor is its fault tolerance capability. However performance deterioration is clearly evident when one phase is removed. This paper presents a fault tolerant power converter, applied to a four phases switched reluctance motor. Some possible additional connections on the commonly used asymmetric bridge converter are introduced to secure the operation of all phases even after a fault occurrence responsible for a power converter switch disconnection. Simulated results indicate that normal operation can nearly be restored at low speed operation and SRM performance behavior is clearly improved at high speed operation. Dynamic operating conditions, under normal and faulty operations with and without the use of the fault tolerant power converter, are analyzed. A high speed operating example, for all the referred operating modes and considering the same speed and load conditions, is presented. Time-domain waveforms of the phase currents, power converter supply current, electromagnetic torque and mechanical speed are presented as well as the spectral analysis of the power converter supply current and electromagnetic torque.