A high-efficiency DC-DC converter with LC resonant in the load-side of HFT and voltage doubler for solar PV systems. (2017) - Sayed, Khairy
This paper presents the implementation of a prototype phase-shift soft-switching full-bridge PWM DC-DC power converter isolated by a high-frequency transformer (HFT). This circuit topology is based on a new concept of series resonant principle in the secondary side. The step-up HFT and the voltage doubler rectifier make this circuit suitable for low-voltage renewable sources such as fuel cell or PV applications. Meanwhile, all semiconductor switches can achieve zero-voltage soft-switching (ZVS) with the assistance of transformer leakage inductances and lossless capacitive snubbers. The new contribution of this work is that the passive semiconductor switches (diodes) on the secondary side can also perform ZVS and zero-current switching (ZCS) transitions with the assistance of voltage doubler capacitance. The theory of operation and the experimental setup of the proposed circuit with a rated output of 5 kW are presented and discussed. A comparison between simulation and experimental results is explored and illustrated.