Proposal of Optimal Design Method for Capacitance in Operating Area Expandable SR Motor Drive Circuit

Authors have proposed a novel drive circuit for SR motor expanding operating area under limited source voltage adding external capacitor in series to extend supply voltage. However, capacitance of the external capacitor enough to extend the driving range of the SR motor has not been optimized. And then, the authors have proposed a conservative design method for capacitance using the linearization of winding current. However, there was a problem that the difference between the conservative design and the fluctuation of the capacitor voltage by simulation was large. In this paper, an optimal design method of capacitance using LC equivalent circuit at the beginning of excitation and demagnetization is proposed.