Criteria for design of high performance switched reluctance motor

Switched reluctance motor (SRM) is an attractive alternative to permanent magnet (PM) based machines and induction machines in many applications. This is because of its simple and rugged construction and fault tolerant capability. Further, no PM is required for its operation. However, SRM has lower torque density than that of PM machine. Recently it was shown that torque density of SRM can be increased by using higher number of rotor poles than stator poles. However, it is found in this paper that such SRM topologies have higher inverter volt-ampere rating and lower overload capability. Hence, use of such machines is restricted to low power applications. For high power applications, it is found that multiplicity of SRM topology is more suitable. Thus, selection of slot pole combination of SRM depends on application. A slot pole combination yielding good performance in one application may not be suitable for another. In view of this, guidelines to select slot-pole combinations of SRM for different applications are developed in this paper.