PLL control scheme for high performance SRM drive

The switched reluctance motor (SRM) provides good adjustable speed characteristics. However, higher torque ripple is one of a few disadvantages of SRM drives. The SRM has torque ripple if it is not operated with an MMF current specified for switching angle and phase voltage. This paper describes the robust control scheme that permits the developed torque to be flat by using a PLL (phase locked loop) controller. In this control scheme, the locked phase signal of the PLL robustly controls the switching dwell angle and its loop filter signal controls the switching voltage adaptively. Experimental results show that stable dynamic performance is obtained for torque and speed together with low torque ripple on the operation of variable loads.