Nonisolated High Step-Up Soft-Switching DC-DC Converter With Interleaving and Dickson Switched-Capacitor Techniques

In this article, a nonisolated high step-up soft-switching dc-dc converter is proposed, which is based on a hybrid structure comprising an interleaved boost converter and Dickson switched-capacitor (SC) networks. The high voltage gain can be achieved by the SC networks without an extremely large duty cycle, and the voltage stresses of all the active switches and diodes are kept at levels much lower than the output voltage. Compared with the traditional SC converters, the proposed converter can achieve continuous voltage regulation by the pulsewidth modulation (PWM) technique. The interleaving operation can reduce the input current ripple and improve the power capacity. Resonant inductors with small inductances are inserted into the SC networks to avoid the high current spikes that occur in the traditional SC converters. All the active switches can achieve zero-voltage switching (ZVS) turn-on. Some of the diodes can achieve zero-current switching (ZCS) turn-off, and the other diodes achieve reduced turn-off di/dt rates. The operating principle and essential steady-state characteristics of the converter are analyzed in detail. Finally, a prototype converter with an input voltage of 25-40 V, an output voltage of 400 V, and a rated power of 1 kW is designed and implemented to verify the theoretical analysis.