A Metamaterial Coupled-Inductor-Based High-Gain DC–DC Converter With Low Ripple for Renewable Energy System

In this article, a novel high step-up DC-DC converter is proposed for renewable energy applications, featuring low input current ripple and enhanced efficiency. The coupling efficiency is significantly improved through the utilization of a metamaterial coupled inductor (MCI). Additionally, an auxiliary circuit is employed to achieve a low input current ripple, which notably reduces the size of the input inductor. The integration of switched capacitors and coupled inductors facilitates high step-up capabilities without necessitating extreme duty cycles, thereby reducing voltage stress and conduction losses on the power switches. The leakage inductance of the coupled inductor allows for controllable current drop rates and alleviates the reverse recovery issue of the output diode. Furthermore, the incorporation of an active clamp circuit not only suppresses voltage spikes induced by leakage inductance but also enables zero-voltage switching (ZVS) for both the main and auxiliary switches. This article presents the operating principle of the proposed topology, the design of the metamaterial coupled inductor, and analyses of input current ripple, voltage gain, voltage stress, power losses and ZVS of power switches. Lastly, a 400W prototype is implemented to validate the performance of the proposed converter.