Optimized operating mode of current-fed dual half bridges dc-dc converters for energy storage applications

This paper presents a thorough study for current-fed dual half bridges (DHB) dc-dc converters over the whole operating range under phase-shift and duty cycle control. An optimized operating mode achieving minimum root-mean-square (rms) transformer primary current is derived in this paper under soft-switching conditions. The analysis and experimental results show that this operating mode has less power loss at higher output power range. This finding provides a design guideline to optimize the current-fed DHB converter performance for energy storage elements applications, especially for ultracapacitor that has a wide variation input voltage. Since current-fed DHB converters can be extended to multi-port and multi-phase applications, this research also provides a base to study the optimized operating conditions for those topologies.