A novel isolated buck converter with output voltage ripple reduction by a complementary square-wave scheme

This paper presents a novel isolated buck converter with output voltage ripple reduction by a complementary square-wave scheme. The converter is composed of a forward DC-DC converter, a half-bridge inverter, and a common LC filter. The outputs of forward converter and halfbridge inverter are connected in series, so that their square-wave outputs are added to form one constant DC voltage. The LC filter is used to remove the output ripples, which are induced by light loading, and noise of the DC voltage so as to obtain a steady output voltage. The circuit can also lower the switching frequency, and decrease the circuit transient response effect of one LC filter. So it is one easily controllable isolated DC-DC buck converter with high stability and low cost. Simulation results have been provided confirm the proposed method. Experiment will also be done soon to verify the performance.