Zero-voltage-switching full-bridge converter with low filter requirement and voltage oscillation amplitude

This article presents a new full-bridge converter with three-winding coupled inductor. The proposed converter can solve the drawbacks of traditional full-bridge converter, such as narrow zero-voltage-switching range, serious voltage oscillation, and large primary circulating current. By introducing a coupled inductor into the full-bridge converter, the currents of leading-leg and lagging-leg are optimised and a wide zero-voltage-switching range can be achieved. In the proposed converter, the secondary voltage oscillation occurs only when the rectified voltage is low. Thus, the amplitude of voltage oscillation and the voltage stress of rectified diodes are well suppressed. Furthermore, the primary power can be continually transferred to the output side during the whole switching period, resulting in reduced circulating current and low filter requirement. Finally, the theoretical analysis is verified on a laboratory prototype. Experimental results show the effectiveness of the proposed converter.