A dual-active-bridge converter-based high step-up converter with voltage-multiplier for high-efficiency PV application

A high step-up soft-switching converter based on combination of a dual-active-bridge (DAB) converter and a voltage multiplier is proposed for high efficiency photovoltaic (PV) applications. With dual-phase-shift modulation, zero-voltage-switching (ZVS) can be realized for both primary-side and secondary-side MOSFETs in a wide load range and the reverse recovery problem of rectifier diodes can be eliminated naturally, which helps high efficiency conversion be achieved. Meanwhile, leakage inductance of transformer is utilized for power transfer and the voltage spike problem caused by leakage inductance is overcome. Owe to use of power transfer inductor and voltage multiplier, the voltage stresses of primary-side and secondary-side power devices are clamped to the input voltage and half of output voltage. The operation principle is analyzed in detail and experimental results with a 500W, 40-56V to 380V prototype are provided to verify the effectiveness and advantages of the proposed converter.