Novel Zero-Voltage Switching Control Methods for a Multiple-Input Converter Interfacing a Fuel Cell and Supercapacitor

An improved multiple-input bidirectional dc-dc converter for application in a fuel cell system is presented in this paper. The converter interconnects a fuel cell, supercapacitor, and load by a combination of a dc-link and magnetic-coupling. Some novel control methods for the proposed multiple-input converter are developed. An easy-to-implement variable hysteresis band control is proposed to achieve zero-voltage switching (ZVS) for the supercapacitor side half-bridge without auxiliary devices. Furthermore, in order to handle the wide variation of the fuel cell voltage while keeping ZVS, an asymmetrical wave control method is introduced. In this way, ZVS is achievable over the entire operating range. Simulation and experimental results that verify the effectiveness of the control methods are presented