Non-isolated high step-up dual-input DC-DC converter with zero-voltage transition

In this paper, a non-isolated dual-input DC-DC converter with zero-voltage transition (ZVT) is proposed for renewable energy systems. The proposed converter has high step-up conversion gain without using any transformer or coupled inductors. The proposed structure consists of two boost cells, one diode-capacitor multiplier cell, and one ZVT auxiliary circuit. The main switches turn on and off under zero voltage condition and the auxiliary switch turns on under zero current condition and turns off under zero current and zero voltage conditions. Soft switching conditions, high efficiency, continuous current of input sources, low-voltage stress on switches, and returning the energy of the auxiliary circuit to the boost cell connected to the lower-voltage input are the main advantages of the proposed converter. The steady-state analysis of the converter and operation intervals are discussed. A 160-W prototype of the proposed converter is designed and implemented. Experimental results confirm the theoretical analysis. The efficiency reaches 96.7% at the nominal load by providing soft-switching for all switches. The proposed topology can be extended for multi-input applications by expanding the number of diode-capacitor multiplier and input boost cells.