Nonisolated High Step-Up Soft-Switching DC-DC Converter Integrating Dickson Switched-Capacitor Techniques

In this paper, a nonisolated dc-dc converter with high voltage gain, soft-switching and PWM regulation is proposed. Dickson switched-capacitor (SC) structure is employed to extend the voltage conversion ratio and make the voltage stresses of all the switches and diodes far lower than the output voltage. At the input side of the topology, two boost circuits under interleaving operation can provide small input current ripple and reduce the current stresses of the main switches. The resonant inductors with small inductance are inserted in SC circuits to avoid the high current spikes existing in the conventional SC converters. All the switches can achieve zero voltage switching (ZVS) turn ON. Some of diodes can achieve zero current switching (ZCS) turn OFF, and the reverse recovery problems of the other diodes are alleviated. The operating principle, the voltage gain and soft-switching conditions are analyzed. Finally, a prototype converter with 25-40 V input and 400-V/1-kW output was established to verify the theoretical analysis.