Analytical Derivation of Phase-Current Waveform for Elimination of Torque and Input-Current Ripples of Switched Reluctance Motor Operating Under Magnetic Saturation

Switched reluctance motors (SRMs) have recently attracted researchers attention owing to their robust mechanical construction, high thermal tolerance, and strong cost-effectiveness, which are promising for vehicle propulsion. However, they tend to generate large ripples in the torque and input currents to the inverter; this deteriorates the driving comfort, and damages the battery lifetime. Preceding studies have investigated using the phase currents of SRMs to eliminate these ripples. However, these studies had difficulties in sufficiently eliminating these ripples in operations under magnetic saturation. This study further evolves one of these preceding studies, and proposes a derivation method for the phase-current waveform for improving the elimination of the torque and input-current ripples in operation under magnetic saturation. The proposed method analytically determines the phase-current waveform based on a nonlinear behavior model of the SRM while considering the magnetic saturation. A finite-element-method-based simulation and experiment are performed to evaluate the proposed method. These results reveal the successful reduction of the torque and input-current ripples under the magnetic saturation relative to a preceding study, supporting the appropriateness of the proposed method.