A ZVS-Based Non-Isolated High Step-Up DC–DC Converter With Low Voltage Stress for Renewable Applications

Abstract

A high-gain soft switched step-up dc–dc converter is presented in this article. High gain is achieved at lower duty and turns ratio with a pair of coupled inductors (CIs) and a voltage multiplier. In addition, an active clamp is incorporated to reduce the voltage stress across the main switch. Hence, switches with lower ON-state resistance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R_{ds\mathrm{\scriptscriptstyle ON}}$ </tex-math></inline-formula> ) and lower voltage ratings are employed, reducing both conduction losses and cost. It additionally helps in achieving zero-voltage switching (ZVS) to both MOSFETs. By recycling the leakage energy of the coupled inductors, voltage gain is further increased. It also helps to accomplish zero-current switching (ZCS) turn-on and turn-off of diodes. This further reduces losses and increases further efficiency. Moreover, the reverse recovery problem of the diodes is also mitigated. The working principle, steady-state analysis, and design guidelines have been carried out. Finally, a 500-W hardware setup with an input voltage range of 20–24 V and output of 400 V at a switching frequency of 50 kHz is built to validate the performance of the proposed converter. The operating efficiency at full load is observed as 95.11%.