A Non-Isolated Coupled Inductor Soft Switched Step-Up DC–DC Converter With Reduced Voltage Stress on Semiconductors

Abstract

This paper presents an optimized design for a non-isolated high step-up DC-DC converter based on the classic Buck converter, integrating a coupled inductor and voltage multiplier technique. In this setup, capacitors are charged in parallel and then stacked in series onto the output capacitor through the coupled inductor, achieving a significant voltage boost at an optimal duty cycle. The use of the synchronous classic Buck converter enables the utilization of low-voltage MOSFETs (less than 100 volts). Moreover, the leakage inductance is effectively utilized to achieve Zero Current Switching (ZCS) for the diodes, and Zero Voltage Switching (ZVS) is realized on all switches using the magnetizing inductance and a capacitor. The performance of this proposed converter was analyzed for PV panel applications through simulations in PLECS/MATLAB, with results validated by practical experiments on a 100-watt hardware prototype developed in the laboratory. The designed converter achieves a maximum efficiency of 96.2 percent, with a voltage gain ratio of 6 for a duty cycle of 0.5 at a turn ratio of 2.2.

Keywords

• DC–DC converter
• high step-up
• voltage stress
• zero voltage switching
• coupled inductor