High efficiency single-pulse controlled switched reluctance motor drive based on novel multilevel converter

Abstract

Due to the high back electromotive force and short commutation time at high speed, the phase current of switched reluctance motor (SRM) is difficult to reach a large value, which limits the output performance of the motor in high-speed operation. This paper proposes a novel multilevel converter (MLC) with fast excitation and fast demagnetisation capability, which allows each phase to control independently even in overlapping conduction operation and is suitable for SRM with any number of phases. The excitation current in the rising inductance region is increased by high-voltage fast excitation, thus increasing the phase current level of the motor at high speed; the current tailing in the falling inductance region is suppressed by high-voltage fast demagnetisation, thereby reducing the generation of negative torque. Based on the novel MLC, a maximum torque per ampere (MTPA) control strategy is designed, and closed-loop control of the boost capacitor voltage is developed. By optimising control, the output torque and efficiency of switched reluctance motor drive (SRD) are greatly improved, and the constant power operation range is extended. Simulation study and experimental results verify the effectiveness of the proposed scheme.