PWM half-bridge zeta converter utilizing resonant technique for reduced peak current

Abstract

The PWM half-bridge zeta (HBZ) converter is one of the most attractive dc-dc converters for wide-input-voltage applications due to its extended duty ratio above 0.5 and soft switching capability. However, it suffers from large peak current stress in the primary and secondary devices. To relieve these drawbacks, a PWM resonant HBZ converter is proposed. The proposed converter can effectively reduce its peak current stress by utilizing a leakage inductor and secondary capacitor as a resonant tank. Therefore, the turn-off switching loss and reverse recovery on the diode are reduced by a sinusoidal-shaped current without any additional components. As a result, the proposed converter can improve its efficiency. To confirm the validity of this paper, a prototype with 300-400V input, 56V/250W output is tested.