Research On Soft Switching Full Bridge Converter With Auxiliary Circuit

This paper focuses on a novel Zero-Voltage-Switching(ZVS) pulse width modulated (PWM) Full-Bridge converter employed passive auxiliary circuit firstly. With this auxiliary circuit, the full bridge converter can achieve ZVS independent of input voltage and load conditions. In addition, the duty cycle loss and secondary-side ringing can be decreased in comparison to traditional Full-Bridge converter. The auxiliary circuit is composed of passive components, and the structure of the topology is simple. Using PWM phase shift control makes the design of control circuit easy. Based on the analysis of operating principle, a criterion of design is given, the simulation and experiment results verify the feasibility of the converter.In view of the analysis mentioned above, an improved ZVS PWM Full-Bridge converter employed passive auxiliary is proposed in this paper. Both of the auxiliary circuits have the same components, but the components connection mode has been changed. The main switches of improved ZVS PWM Full-Bridge converter can also operate at ZVS. Moreover, auxiliary circuit supplies all of the energy to switches for ZVS, and the efficiency of the converter can be increased. Simulation and experiments rated 1500W are also provided in this paper as an example to verify the performance of improved ZVS PWM Full-Bridge converter employed passive auxiliary circuit.A novel Zero-Current-Switching(ZCS) Full-Bridge with auxiliary resonant circuit has been presented in this paper at last. The auxiliary located at the primary of main transformer. The main switches and auxiliary switches can achieve ZCS at wide load range, and the current stress of main switches doesn't increase. Diodes of auxiliary circuit are softly commuted. A 1500W/50kHz prototype converter is built to confirm the effectiveness of the presented converter.