Application of current-fed quasi-Z-Source Inverter for traction drive of hybrid electric vehicles

This paper presents a novel current-fed quasi-Z-source inverter (qZSI) used to replace the two stages of bidirectional DC-DC converter and conventional pulsewidth modulation inverter to control the power to the motor, and the state of charge (SOC) of the battery in hybrid vehicles. Besides the advantages inheriting from the ZSIs, the qZSIs also have their own merits. This paper presents a comprehensive study on the new features of the current-fed qZSI, including the advantageous buck-boost function, improved reliability, reduced passive component ratings, and unique regeneration capability. The current-fed qZSI are bidirectional with an additional diode, unlike the voltage-fed Z-source inverter than a switch to achieve bidirectional power flow. A reverse blocking IGBT (RB-IGBT) based current-fed qZSI prototype is developed in laboratory. Both simulation and experimental results are shown to verify the theoretical analysis.