Triple-Mode Isolated Resonant Buck–Boost Converter Over Wide Input Voltage Range for Residential Applications

This article proposes a triple-mode isolated resonant buck-boost converter over a wide input voltage range for residential applications of photovoltaic arrays and fuel cells. First, in case that the input voltage is smaller than the nominal voltage, it operates in a resonant-boost mode that boosts the input voltage by using a bridgeless structure on the secondary-side. Next, if the input voltage is within the range of the nominal voltage, it operates in a fully series-resonant mode, which results in high efficiency by the soft-switching on the primary-side switches and reduced conduction loss. Last, if the input voltage is more than the nominal voltage, it operates in a pulsewidth modulation series-resonant buck mode, which can achieve the step-down conversion by reducing the duty cycle. Unlike the conventional resonant converters, the proposed converter achieves high efficiency and less number of power components over a wide input voltage range. Finally, the performance of the proposed triple-mode isolated resonant converter has been fully verified on a prototype 400 W test-bed in the wide input voltage of 35-65 V.