Design procedure of segmented rotor switched reluctance motor for direct drive applications

Switched reluctance motors (SRM) are becoming increasingly popular because of the rising cost of permanent magnets. It was reported that segmented rotor construction improves the torque output and efficiency. This study discusses an SRM with segmented rotor construction designed for direct drive application. Such a motor has an outer rotor. It is found that in such machines, the torque output increases when there are higher number of rotor segments than stator poles. A segmented rotor SRM with 12 stator poles and 26 rotor segments is discussed here. It has unique pole tip shape, which improves torque output. Design procedure of the motor is presented. Moreover, limitations of segmented rotor SRMs having a higher number of rotor segments than stator poles are also identified, and possible solutions are suggested. Experimental results on the prototype of a three-phase 12/26 motor are presented.