Development of high efficiency current-fed quasi-Z-source inverter for HEV motor drive

This paper presents the development and high efficiency design considerations of a current-fed quasi-Z-source inverter for hybrid electric vehicle (HEV) motor drive using reverse-blocking (RB) IGBT. In order to overcome the unidirectional power flow and the voltage buck operation inability problems of traditional current-source inverter for motor drive applications, a current-fed quasi-Z-source inverter (CF-qZSI) has been proposed. By adding a diode and a LC network, CF-qZSI is able to achieve bidirectional power flow and voltage buck operation function. In order to achieve high efficiency for CF-qZSI, proper modulation method selection and careful passive components design are needed. The space vector pulse width modulation (SVPWM) method for this inverter to achieve proper voltage gain and less switching loss is discussed. The active device and passive components stress are analyzed. A high efficiency coupled inductor for CF-qZSI is designed and developed. A 15 kW prototype of CF-qZSI is built, experimental results with the efficiency up to 98% are provided.