Analytical Derivation of Phase Current Waveform Eliminating Torque Ripple and Input Current Ripple of Switched Reluctance Motors under Magnetically Saturated Operation

Abstract

Switched reluctance motors (SRMs) is beneficial in excellent cost-effectiveness and high thermal tolerance owing to their simple mechanical construction free from permanent magnets. Nevertheless, application of SRMs to vehicular propulsion is often hindered by their comparatively large input current ripple and torque ripple. For mitigating the problem, the previous study has proposed a phase current waveform that eliminates both of these ripples under the magnetization below the magnetic saturation. However, this previous technique still suffers from significant torque and input current ripples at large output torque, which tends to cause the magnetic saturation. This paper proposes an improved phase current waveform that eliminates these ripples even at large output torque. This waveform was derived analytically based on the nonlinear magnetic model of the SRM. The proposed phase current waveform was successfully verified by the experiment, suggesting the usefulness of the proposed technique for applying SRMs to vehicular propulsion.