A Torque Ripple Suppression Strategy for Hysteresis Segmented PWM-DITC Permanent Magnet Assisted Switched Reluctance Motor

Abstract

In the traditional Direct Instantaneous Torque Control (DITC) strategy for permanent magnet assisted switched reluctance motors, the hysteresis control mode during the commutation phase and single-phase on-period is not smooth, resulting in excessive synthetic torque ripple. In this paper, we analyzed this problem, combined with the principle of hysteresis segmentation control and pulse width modulation (PWM), and proposed a hysteresis segmented PWM-DITC strategy. By analyzing the torque error changes in each division area of the inductor, the torque error is adjusted by the internal hysteresis loop during the commutation period and single-phase on-period, so that the hysteresis control is smoother, and the torque ripple is reduced. At the same time, the linear model of rotor angle and inductance is established; the PWM voltage modulation calculation formula at both ends of the winding is calculated and derived; the hysteresis output signal at the commutation time and the single-phase on-time is optimized to further suppress the torque ripple. Finally, through simulation and experimental demonstration, the proposed hysteresis loop segmented PWM-DITC strategy can overcome the problem of unsmooth hysteresis control mode and can effectively suppress torque ripple.