Double boost-flyback converter

A high-gain step-up non-isolated dc–dc converter is proposed in this study, named the double boost-flyback converter. The topology combines two conventional boost-flyback converters with input-parallel and floating-output connections. The new topology increases the static gain and reduces the input current ripple in relation to the conventional boost-flyback topology. The proposed converter has the potential to be used in low input voltage applications that require a high gain, such as systems powered by photovoltaic panels, fuel cells, electric vehicles, and low voltage batteries. This study provides details on the principle of operation, static gain, control strategy, design guide and experimental verification. A 1 kW prototype was designed and built for an input voltage of 48 V and an output voltage of 800 V, reaching a static gain of 16.67. The maximum efficiencies obtained were 94.6% at 70% of load and 93.9% at rated load.