Quasi-Z-Source-Fed SRM Drive for Torque Ripple Minimization and Speed Range Extension With Three-Switch Conduction
Qingguo Sun, Limei Chen, Xu Liu, Feng Niu, Chun Gan
Abstract
This article proposes a quasi-Z-source (QZS)-based modular switched reluctance motor (SRM) drive to suppress the source current ripple, minimize the torque ripple, widen the constant torque range and speed range, and enhance the system reliability. To take full advantage of the QZS unit and modular power modules, the QZS-based modular SRM converter is first constructed. Subsequently, a three-switch conduction-based current compensation mechanism is developed to deal with the torque plummet issue caused by the inherent series excitation mode. Meanwhile, a novel four-region direct instantaneous torque control strategy is proposed to further suppress torque ripple. Furthermore, a voltage regulation method based on a compensation mechanism is developed to suppress the source current ripple and provide great assistance in implementing the above-mentioned strategy more effectively. In addition, the shoot-through state can be evenly distributed among the four bridge arms, which is conducive to balance the heating dissipation of power devices for an improved service life of the power converter. To validate the feasibility and effectiveness, the experiments are carried out on a 150-W three-phase 12/8 SRM prototype.