This paper proposes an isolated DC-DC converter with a highly flexible voltage gain, which can be adjusted by three independent parameters. The proposed converter also offers the smooth input current, a simple structure and high efficiency. The only switch of the converter experiences extremely low voltage spikes; its output diode works under the zero current switching (ZCS), leading to reduced switching losses and overall converter costs. Low magnetizing current of coupling inductors and low voltage stress of capacitors of this converter indicates its high power density. The input current ripple reduction technique is independent of the coupling factor and can be easily implemented in the converter. The operating principle and parameter design guideline of the proposed converter are explained in detail, and its performance is compared with two existing DC-DC converters. To further validate the proposed converter, a 400 W prototype is built and tested in the laboratory.

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