Research On Zero-Current Soft Switching Full-Bridge Converter Using Auxiliary Circuit

For the rapid development of power electronics technology,the high-power DC conversion technology is playing a vital role.With the advantages of simple topology,easy control,and high efficiency,the full-bridge converter is widely used in high-power applications such as power supply,renewable energy,energy storage systems,and electric vehicle traction systems.Therefore,researching bridge converters are of practical significance.In recent years,scholars have put forward soft-switching full-bridge converters to achieve a compact,lightweight,and high-frequency switching power supply system.Based on research the full-bridge converter and its soft-switching technology widely,this paper analyzes several typical full-bridge DC/DC converters and its soft-switching realize conditions and problems it brings.The soft-switching realize methods of full-bridge DC/DC converters with different soft switching technologies are classified and summarized.Aiming at the problem of complex auxiliary circuit,large circulating current loss and large voltage and current stress in the existing zero-current switching full-bridge converter,a novel zero-current soft-switching full-bridge DC converter based on auxiliary circuit and its modulation strategy has been proposed.In this paper,a novel zero-current switching(ZCS)full bridge(HB)DC/DC converter based on auxiliary circuit and its modulation strategy has been proposed.Compared with the existing ZCS HB DC/DC converter,the auxiliary circuit is simple.It can realize zero-current turn-on(ZCS)and zero-voltage and zero-current switching(ZVZCS)of the primary switch and zero-voltage zero-current turn-on(ZVZCS)and zero-voltage switching(ZVS)of the auxiliary switch.It reduces circulation loss and does not increase the current stress of the primary switches and the voltage stress of the rectifier diodes.The diodes turn off naturally when the current decreases to zero,thus,there is no reverse recovery current and loss on diodes.The operation principle,steady-state characteristics and soft switching conditions of the converter are analyzed.Besides The effects of the turn-off delay time between the auxiliary switch and the primary switch and the resonant element on the output voltage characteristic under open-loop control are discussed.Finally,the Cadence simulation and 740V/1kW and 100kHz experimental prototype was established.The effectiveness of the converter is verified by simulation and experimental results.