A novel type high-efficiency high-frequency-linked full-bridge DC-DC converter operating under secondary-side series resonant principle for high-power PV generation

This paper is mainly concerned with the development of a new state-of-the-art prototype, high-efficiency, phase-shift, soft-switching, pulse-modulated, full-bridge DC-DC power converter with a high-frequency power transformer, which is designed for utility-grid-tied photovoltaic (PV) power inverters. The proposed high-frequency transformer (HFTR) link DC-DC converter topology is based on a new conceptual secondary-side series resonant principle and its inherent nature. All the active power switches on the HFTR primary side can achieve lossless capacitive snubber-based zero-voltage switching (ZVS) with the aid of transformer parasitic inductances. Moreover, passive power switches on its secondary side can also perform ZVS and zero-current switching (ZCS) transitions for input voltage and load variations. First, the operation principle of the newly proposed DC-DC converter and some of its noteworthy features are described in this paper on the basis of the results of analysis by simulation. Then, the experimental setup of the DC-DC converter with an output of 5 kW treated here is demonstrated and its experimental results are discussed from a practical viewpoint. Finally, some comparative evaluations between simulation and experimental data are discussed and considered, together with future works.