A new soft-switching high gain DC/DC converter with bipolar outputs

This paper introduces a new single-input multi-output step-up DC/DC converter with soft-switching performance and low input current for renewable energy applications. The proposed topology uses a three-winding coupled-inductor (TWCI) and voltage multiplier circuits to achieve high voltage gains. The bipolar output voltages of the proposed converter can be varied independently by tuning the turns ratios of the TWCI. Due to the semi-trans-inverse specification of the suggested topology, high voltage gains can be obtained under a lower number of turns ratio in the magnetic device. Furthermore, a regenerative passive clamp technique mitigates the voltage stress on the single power switch. Additionally, the power dissipations are further reduced by considering a resonant tank in the circuit. In the converter, the parasitic leakage inductances of the TWCI windings help to provide the soft-switching conditions for the switch and also to eliminate the reverse-recovery loss for all converter diodes. The operating mode of the presented converter has been introduced and the steady state, along with the main operating equations have also been derived. Finally, the theoretical analysis is verified by a sample prototype 235 W at the input voltage 25 V and outputs of 200 V and −200 V.