Fully Soft-Switched High Step-Up Nonisolated Three-Port DC-DC Converter Using GaN HEMTs

In this article, a soft-switched nonisolated high step-up multi-input dc-dc converter is proposed. The proposed converter has overcome the hard switching problem of the conventional boost three port converter (boost-TPC) by providing zero-voltage-switching condition for all switches at various operating modes. The proposed converter uses coupled inductors technique to enhance the voltage gain and utilizes the leakage inductance energy and the energy storage device power path to provide soft switching condition. In addition, the voltage stress of the main switch is reduced which has led to utilizing low R-ds(ON) switches. Various converter operating modes are presented and design considerations are discussed. To evaluate the proposed converter performance, two prototypes of the proposed converter are implemented utilizing the latest generation gallium nitride high electron mobility transistors and the mature Si MOSFETs technology. The results show that the proposed converter efficiency is enhanced in comparison with the conventional boost-TPC converter.