A novel zero-voltage zero-current switching full-bridge PWM converter using improved secondary active clamp

A novel FB-PS-ZVZCS converter is proposed. By turning on the clamping mosfet during the primary current circulating period, this converter clamps the voltage of the output filter inductor to zero, so the voltage of the output filter capacitor is reflected to the primary and applied on the leakage inductance to quickly reset the primary circulating current. This new topology has advantages in several aspects such as effective ZVZCS range, maximum duty cycle and so on. The operations and characteristic of the new topology are presented in details; the feathers, analysis and design considerations are illustrated and verified on a prototype. Both the theoretical analysis and the experimental result prove that the new topology suits high power and high output voltage application perfectly.