Torque ripple reduction of switched reluctance motors considering copper loss minimization

Discrete torque generation mechanism and inherently nonlinear magnetic characterization of switched reluctance motors lead to unacceptable torque ripple and reduce the variety of applications in industry. In this paper, a phase current profiling technique is proposed considering magnetic saturation effects as well as minimizing power loss during the commutation area between the adjacent phases. Constant torque trajectories are considered in incoming and outgoing phase currents plane based on nonlinear torque curves which are obtained from experimental measurements. Optimum points on constant torque trajectories are selected based on improving drive efficiency and minimizing copper loss in each rotor position. A modification method is also introduced to enhance torque ripple-free region based on simple logic rules. Compared than conventional torque sharing functions, the resultant reference current from the proposed method has less peak and effective values. Moreover, it also has lower copper loss. Experimental and simulation results on four phase, 4Kw 8/6 SRM, validate the effectiveness of the proposed method.