A sliding mode controller to minimize SRM torque ripple and noise

This paper is an attempt to eliminate the torque pulsation of switched reluctance (SR) motors. It is well known that pulsed radial and tangential forces are the source of acoustic noise problems often mentioned in relation to SR motors. In this study, to control the force pulsations, phase voltage is selected as the control variable contrary to what is often encountered in the literature. The authors believe that cost effective implementation of this choice is now technically possible. Selection of appropriate phase voltages is achieved by sliding mode control in order to produce the pro-defined torque references for each phase. The paper first illustrates via simulations that such an approach effectively eliminates the torque ripple and follows the defined reference, if the derivative of error function is appropriately chosen. The performance of the motor with different choice of sliding mode functions is given. The performance of the final choice is also experimentally illustrated. Various application issues of this type of controller are discussed.