A novel sinusoidal boost-flyback CCM/DCM DC-DC converter

This paper proposed a novel and simple sinusoidal boost-flyback continuous conduction mode (CCM) converter. This converter continuously produces half-sinusoidal voltage to a line frequency DC-AC inverter. This simple boost-flyback structure utilizes a coupled inductor to achieve a wider voltage gain range. The leakage inductance energy of the coupled inductor can be recycled to reduce the voltage stress and power losses. Consequently, the low-voltage rating and low-conduction resistance switch can be selected to reduce conduction losses and improve system efficiency. The magnetizing inductance of the coupled inductor is operated under CCM, and thus, the harmonic content of the output current is reduced. Finally, a 300 W prototype was implemented for feasibility verification. The maximum efficiency is 97.2%, and the full load efficiency is 96.2%. To verify its AC performance, the proposed converter has connected to a full bridge DC-AC inverter to simulate a micro inverter system with the highest efficiency of 96% and 94.5%under full load condition. The output current total harmonic distortion is 1.3%.