Improved Research And Engineering Realization Of Phase-shifted Controlled ZVS Full-bridge Converter

The traditional phase-shifted ZVS PWM full-bridge converter can realize ZVS for the power switches with the leakage inductance of the transformer and the intrinsic capacitors of the power switches. In order to restrain the parasitic oscillation and the voltage ringing of the rectifier diodes, auxiliary resonant commutating network including a resonant inductor and two clamping diodes auxiliary branches can be introduced to the primary side. The converter can be improved just by exchanging the position of the auxiliary branch and the transformer such that the auxiliary branch is connected with the leading leg. So, the improved converter not only restrains the voltage ringing of the rectifier diodes, makes both the secondary side diodes and auxiliary diodes operate on the soft switching state, but also decreases the RMS current of the clamping diodes auxiliary branches and reduces secondary duty cycle loss and the primary current in zero state. Furthermore, the operation principle of the improved converter and the comparison with the original converter are analyzed in this paper. Because of a resistance in the clamping diodes auxiliary branch, the effect of the clamping diodes auxiliary branch is weakened, in order to restrain the parasitic oscillation and the voltage ringing of the rectifier diodes better, a simple RLCD clamping circuit is placed in the secondary side of the full bridge converter, it not only restrains the voltage ringing of the rectifier diodes, avoids the defect of the general RCD snubber network, but also restrains the defect of the big primary circumfluence waste and the great loss of the duty cycle of the conventional zero-voltage-switching full-bridge converter, the detailed operation principle of this full-bridge converter using secondary clamping circuit is analyzed.The improved converter is adopted to the electric operating power supply. The control loop is designed, and the main parameters of the converter and the compensators are also proposed. Finally, a 220V/10A self-cooled prototype converter is built, and the simulation and the experimental results are also included in this paper.