High Step-Up DC/DC Converter for Fuel Cell Hybrid Electric Vehicles

This paper presents a high step-up converter with fuel cell for hybrid electric vehicle power supplies. The fuel cell has the power characteristics of low voltage and high current due to electrochemical characteristic. Thus, a high step-up dc-dc converter is devised for boosting the fuel cell voltage to be a constant dc-bus voltage. The high step-up dc-dc converter with three-winding coupled inductor and clamp capacitor is proposed in this paper, which utilizes a three-winding coupled inductor and double circuit to increase voltage conversion ratio with low duty ratio. The circuit operates in continuous conduction mode, and the fuel cell current ripple can be reduced. The voltage clamped technology is used for reducing the switch voltage stress. Thus, the Schottky diode can be adopted in the output terminal for alleviating the reverse-recovery current and decreasing the switching and conduction losses. Finally, a 2k-Watts power supply with input voltage 60V and output voltage 400V for hybrid electric vehicle power supplies was implemented in the hardware verification. The highest efficiency is 96.81%.