Torque ripple minimization of switched reluctance motor using modified torque sharing function

Abstract

Torque pulsation mechanism and highly nonlinear magnetic characterization of switched reluctance motors(SRM) lead to unfavourable torque ripple and limit the variety of applications in industry. In this paper, a modification method proposed for torque control of SRM based on conventional torque sharing functions(TSF) to improve maximum speed of torque ripple-free operation considering converter voltage limitation. Due to increasing phase inductance in outgoing phase during the commutation region, reference current tracking can be deteriorated especially when the speed increased. Moreover, phase torque production in incoming phase may not be reached to the reference value near the turn-on angle in which the incremental inductance would be dramatically decreased. Torque error for outgoing phase can cause increasing the resultant motor torque while it would be negative for incoming phase and yields reducing the motor torque. In the proposed modification method, phase torque tracking error for each phase under the commutation added to the other phase so that the resultant torque remained in constant level. This yields to enhance motor efficiency compared than the conventional receding turn-on and turn-off angles. An experimental four phase 1.6 KW, 8/6 SRM set of magnetic characterization data used to simulate and validate the effectiveness of the proposed method.