A Quasi-Z-Source Integrated Multiport Power Converter as Switched Reluctance Motor Drives for Capacitance Reduction and Wide-Speed-Range Operation

This paper presents a quasi-Z-source integrated multiport converter (ZIMPC) for switched reluctance motor (SRM) drives to reduce the dc-link capacitance and enable wide-speed-range operation. In conventional SRM drives, employing multiphase asymmetrical H-bridge (ASHB) topology, large capacitors are necessary to absorb the transient energy during phase current commutation. However, electrolytic capacitors would affect the lifetime, cost, and power density of the drive system. With switch multiplexing technique, a ZIMPC is derived to achieve power ripple reduction using relatively small capacitors. The power ripple generation principle and requirement of capacitance in ASHB and ZIMPC are analyzed. The model of the overall system including SRM and the proposed drive is developed using mode analysis. Advanced control method with repetitive control is proposed and developed based on the system model. Also, the ZIMPC can boost the equivalent phase exciting voltage and widen the constant power speed range. At last, simulation and experimental results verify the feasibility of the proposed ZIMPC and its superior performance with smaller capacitance as compared with ASHB.