chapter  4
62 Pages

Converters for SRM Drives

This chapter presents an extension of the Undeland snubber configuration to the two-switches-per-phase converter topology of the switched reluctance machine (SRM) drive including the energy recovery feature. Since the torque in SRM drives is independent of the excitation current polarity, the SRM drives require only one switch per phase winding. The SRM drives always have a phase winding in series with a switch. In case of a shoot-through fault, the inductance of the winding limits the rate of rise in current and provides time to initiate protective relaying to isolate the faults. Snubber studies for SRM drive are nonexistent even though the converter topologies are unique and do not fall under the category of inverter topologies applicable to ac motor drives. Due to the additional stage of power processing in the chopper, the overall system efficiency of the SRM drive system is lower than that of the other schemes without the chopper stage.