Characteristics of switched reluctance motor drive circuit with voltage boost function without additional reactor

Switched reluctance motor (SRM) is attractive for the driving motor of electric vehicles (EVs) and hybrid electric vehicles (HEVs) from the view point in which the motor does not use rare-earth materials. However, the special drive circuit, which is different from general three-phase inverter used for driving permanent magnet synchronous motor and induction motor, is required in order to drive SRM. By the way, in some of commercial HEVs, a boost chopper combined with a three-phase inverter is used in order to apply high voltage to motor windings at high-speed range. In this system, the size of the additional reactor, which is required in boost chopper, is a problem. As a solution of this problem, the authors proposed a novel drive circuit with voltage boost function without additional reactor for SRM. It was verified by experiment in the previous work that the proposed circuit is able to increase the output than a conventional circuit. In this paper, control scheme of the proposed circuit is described briefly. In addition, the characteristics relations among the capacitance used in the proposed circuit, the capacitor voltage ripple and the average output torque are described. Moreover, circuit efficiency was compared between a conventional circuit and the proposed circuit.