A High Step-up Integrated Buck-Boost-Zeta Converter Using Three-winding Coupled Inductor with Current Sharing Considered

This paper proposes a high-gain Buck-Boost-Zeta converter with three-winding coupled inductor, which is generated by differentially connecting the Buck-Boost converter and the Zeta converter and integrating the coupled inductor multiplier cell. An active switched-inductor is obtained at the input side by differential connection, which is used as the primary winding of the three-winding coupled inductor, and the multiplier cell is composed of the secondary winding and diode-capacitor. The diode-capacitor circuit in the topology is multiplexed as a passive clamp branch to absorb the leakage energy and the ZCS turn-on of the switches is achieved. Therefore, the proposed converter achieves higher voltage gain and lower switch voltage stress. At the same time, the proposed converter retains the continuous output current characteristic of the Zeta converter. The operation principles and performances of the proposed converter are analyzed in detail. Meanwhile, the imbalance currents of the primary windings caused by the leakage inductance error is analyzed and the coupled inductor current sharing method is given, which effectively alleviates the current pulsation of the primary winding. A 400W experimental prototype is built to verify the theoretical analysis.