Characteristics of Z-source inverter supply for permanent magnet brushless motors

Z-source inverters (ZSIs) supply AC loads from a DC source and boost the voltage of the DC source in a single stage. Such an ability is much needed in electric vehicles where the rated voltage of the traction motors is usually higher than the voltage generated by the onboard DC sources. Being the technological trend in the traction drives directed toward the employment of PM brushless motors, the use of a ZSI for their supply is a cutting-edge issue, which is investigated in this paper. The paper starts by formulating the equations of a ZSI in a suitable form. Then the characteristics of the ZSI supply for the two basic types of PM brushless motor, namely the DC and AC types, are assessed with regards to the switch solicitation and utilization. As a comparison, the characteristics of the traditional DC-DC boosted inverter supply are also given.