High step-up DC-DC converter with switched-capacitor and its zero-voltage switching realisation

As generally acknowledged, the high step-up DC-DC converter is widely used in the sustainable energy system as the front-end stage of the DC-AC converter. Therefore, a novel high step-up DC-DC converter is proposed in this study. The proposed converter with network of switched-inductor and switched-capacitor can achieve high voltage gain under low duty cycle. Meanwhile, the active switches and diodes suffer from low voltage stress. More importantly, an auxiliary resonant circuit with lower losses and cost is employed to realise zero-voltage switching (ZVS) turned-on and ZVS turned-off for the active switches, resulting in high conversion efficiency. Firstly, the operation principle and steady-state performance are discussed in detail. Then, prototype with power rating of 200 W is built to verify the performance of the proposed converter. The maximum efficiency of the prototype can be up to 96%, and the experimental results agree with the theoretical analysis and the simulation results well.