Quasi-Z Source DC-DC Converter with Wide Step-up/step-down Range for Fuel Cell Vehicles

Hydrogen energy utilization technology represented by fuel cell vehicles has a major impact on improving air quality and reducing other fossil-fuel-related problems. Aiming at the requirements of wide step-up and step-down range, low input current ripple,wide voltage input range and common ground between input and output of DC-DC converters for fuel cell vehicles, a non-isolated buck-boost DC-DC converter based on quasi-Z source structure is proposed by combining quasi-Z source structure with LC network.The converter not only has a wide step-up and step-down range under non-limit duty cycle, but has a continuous input current and input-output common ground structure. Based on the small signal model of the proposed buck-boost converter, the closed-loop control system of the converter is designed. The experimental results show that the proposed converter can effectively achieve 3.8 times step-up and 0.75 times step-down, and the maximum efficiency is 96.17% at rated power. When load disturbance and voltage step