Analysis and Design of a Nonisolated High Step-Down Converter with Coupled Inductor and ZVS Operation

This article presents a detailed analysis and design of a high step-down converter. The proposed converter achieves high step-down voltage gain without the need of extreme duty cycles by using coupled inductor. The converter features low switch stresses, which reduces the conduction loss by using low voltage MOSFETs. Moreover, the magnetizing current of the coupled inductor is zero, which reduces the magnetic size. The leakage energy of the coupled inductor is recycled. Zero voltage switching is achieved to reduce switching loss and improve the EMI performance. In addition, continuous output current is achieved; hence, small filtering capacitor can be used. A hardware prototype is built and experimental results verify the feasibility of the step-down converter.