Dual-coupled inductors-based high step-up DC/DC converter without input electrolytic capacitor for PV application

To alleviate the power losses caused by the fluctuation of the output current of the photovoltaic (PV) array, a DC/DC converter with high-voltage gain is proposed for PV generation systems. The input current ripples of the proposed converter can be greatly reduced by making use of coupled inductors. Then the electrolytic capacitor on the input side could be replaced by polypropylene capacitor with smaller capacity and size. In addition, the snubber and the energy recovery circuits constructed by diodes and storage capacitors can be operated to reduce the voltage spikes of the switch tubes and losses caused by the leakage inductance. Based on analysing the inherent five operating modes of the proposed converter, high-voltage gain and the zero input current ripples characteristics of the proposed converter is manifested. The theoretical analysis is then verified by a 150 W-rated experimental prototype, and the results show that the proposed converter can quickly and accurately trace the maximum power point of PV array based on the modified incremental conductance method with high-voltage gain and low current ripples.