A Capacitor Clamped H-Type Boost DC-DC Converter With Wide Voltage-Gain Range for Fuel Cell Vehicles

Abstract

In order to use the dynamic low-voltage fuel cell stack in a fuel cell vehicle with a constant high voltage (400 V) dc bus, a capacitor-clamped H-type boost dc-dc converter with a wide voltage gain is proposed in this paper. In the input-voltage side, a capacitor clamped H-type structure is adopted to reduce input current ripple, avoid narrow-pulse of pulsewidth modulation voltage waveforms, and decrease the conduction loss of power switches; while in the output-voltage side, a switched-capacitor structure is adopted to achieve high voltage gain and decrease the voltage stress of all power semiconductors and capacitors. The operating principle, characteristic, control strategy, parameters design, and comparison with other converters are analyzed, and a 400 W prototype is developed. As a result, the converter can transform low-voltage from 25 V to 70 V in to 400 V with a wide voltage-gain range, which maximum efficiency is 94.72%. The experimental results also validate the aforementioned characteristics of the proposed converter and the correctness of theoretical analysis. This converter is suitable to serve as power interface for fuel cell vehicles.