Z-source resonant DC-DC converter for wide input voltage and load variation

This paper presents a novel resonant dc-dc converter using Z-source impedance network. The conventional series resonant converter suffers from efficiency degradation problem when the input voltage range is wide because the switching frequency of converter should be increased far away from resonant frequency to control output voltage. The proposed Z-source resonant dc-dc converter can minimize switching frequency range of the converter and can lead to high converter efficiency over the entire input voltage and load variation. In addition to that, the proposed converter can be short- and open-circuited without damaging switching devices. Thus the proposed converter is very strong to EMI and converter reliability can be greatly enhanced. Finally, bulky inductors and capacitors in the Z-source network are reduced significantly while maintaining the same converter performance. A dc-dc converter using the proposed concept is built and tested. Its performances are verified with experimental results.