High step‐up dual full‐bridge ZVS DC–DC converter with improved integrated magnetics and new resonant switched capacitor cell

Abstract

A high voltage gain dual interleaved full bridge converter with Zero Voltage Switching (ZVS), improved integrated magnetics, and a new resonant Switched -Capacitor-Cell (RSC) is presented. By taking the advantage of a new resonant switched capacitor cell and transformers with low turn-ratio as well as low leakage inductances, the desired high output voltage can be obtained. Furthermore, the output diodes operate in Zero Current Switching (ZCS) condition, and switches are maintained under ZVS condition over the whole range of output load variations. In addition, switches turn off near zero current leading to high overall efficiency. An interleaved approach (multi-cell) is adopted over a single cell to increase the power handling capacity. Furthermore, transformers of dual cells are integrated into a single UU core which cuts down the total volume of the converter as well as the total core loss. Since secondary windings have opposite polarities, there exists no DC flux, and the top and bottom RSC cells operate in 180 degree out of phase. Taking the aforementioned characteristics into consideration, the proposed converter has a good performance for high voltage applications. Experimental results of a 3 kw prototype with an output voltage of 16 kV validate the features of this topology.