Study And Design Of Zero-Voltage And Zero-Current-Switching PWM Full Bridge Converter Using Two Diodes In Series With The Lagging Leg

Modern power supply is becoming smaller and lighter, which requires DC/DC converter be lighter in weight and smaller in size. To meet this requirement, it is necessary to make the DC/DC converter work in high frequency. When devices switch in high frequency, switching losses and switching noise will become serious problems. Therefore, the soft-switching technology, which can solve these problems effectively, is paid wide attention both at home and abroad.Phase-shifted (PS) ZVZCS full bridge converter achieves zero-current switching for the devices due to the eliminated circulating current. The converter reduces the conduction loss and improves the efficiency, so it is suitable for high power application.The paper analyzes a ZVZCS FB-PWM converter using two diodes in series with the lagging leg. The method of transformer, filter inductor and component parameter design is presented in this paper and simulated by Matlab. On the state space analysis and small-signal model analysis of this topology, this paper introduced the average current mode control system based on UC3875. Meanwhile, the paper does elementary study on the EMC of the converter, providing some theoretical basis to improve the system anti-jamming capaility.A 1kW (400V input and 200V/5A output) DC/DC converter is implemented in the laboratory. The experimental results are in accord with the theoretical analysis.