A high step-up DC-DC converter with switched-capacitor and switched-inductor using one coupled inductor

This paper proposes a high step-up DC-DC converter which integrates switched-inductor and switched-capacitor techniques with a four-winding coupled-inductor. With switched-inductor technique, two primary windings of the coupled-inductor are charged in parallel and discharged in series to obtain high voltage gain. Moreover, by adding two sets of diode-capacitor circuits on both primary side windings, not only can recycle the energy causing the voltage spike on the power switches, but can also lift the conversion ratio. Then, the power switches with lower voltage stress are used to improve the efficiency of the proposed converter. The operating principle, steady state analyses, and key parameters design of the proposed converter are discussed and provided. Finally, a 400 W laboratory prototype with 24 V input voltage and 480 V output voltage is constructed and tested to validate the performance. The highest and full load efficiencies are 95.8% and 94.8%, respectively.