Topology Improvement And Sneak Circuit Study On Complex Power Converters

With the rapid development of power electronics technology,lightweight and high frequency have become the important directions of power electronics development,which is leading better application to the soft switch technology in the power converter.Soft switch technology can effectively improve the output efficiency and reduce the interference of high frequency environment to the converter.However,the soft switch technology also increases the complexity of the converter,causing undesired paths and sneak circuit in the converter.The appearance of the sneak circuit will affect the working process of the soft switch,and even cause more serious circuit failure.Therefore,in order to realize the soft switch working process of the converter and avoid the occurrence of the sneak circuit,the sneak circuit analysis and circuit structure optimization of the complex power converter are carried out in this paper.In this paper,the phenomenon of sneak circuit in traditional converter is introduced firstly,and the influence of sneak circuit on traditional converter is pointed out.Therefore,in order to improve the conversion efficiency of the traditional Boost converter and reduce the influence of the sneak circuit,this paper adds the resonant unit to the traditional Boost converter and names it as the Zero Voltage Transition(ZVT)Boost converter.Compared with the traditional Boost converter,the proposed converter realizes the soft switch working process of all switching devices to improve the output efficiency of the converter,improve the gain of the converter and reduce the influence of the sneak circuit on the converter.In this paper,the working modes of ZVT Boost converter in a period and the soft switch working process of all switching devices are analyzed in detail.Meanwhile,the phenomenon of sneak circuit in ZVT Boost Converter is analyzed.Though the ZVT Boost converter can improve the efficiency,the switching tube of the converter is subjected to a large voltage stress and the path of the sneak circuit is complicated,which affects the safety of the converter.Therefore,this paper further improves the topology of ZVT Boost converter on the premise of not adding components.Compared with the original ZVT Boost converter,the improved ZVT Boost converter reduces the maximum voltage that the switch tube is subjected to and further reduces the sneak circuit path in the converter.In order to ensure the realization of the soft switch of ZVT Boost Converter,this paper analyzes in detail the working mode of the improved ZVT Boost Converter and deduces the conditions for the occurrence of soft switch.At the same time,the path of the sneak circuit is identified by graph theory analysis method and the trigger condition of the sneak circuit is deduced to avoid the occurrence of the sneak circuit.Combining with the theoretical analysis of the improved ZVT Boost Converter,this paper makes a reasonable design of the parameters of the converter to ensure the realization of the soft switch working process and the effective avoidance of sneak circuit phenomenon.Finally,the simulation model in PSIM software and experimental prototype of the improved ZVT Boost Converter are built,and the improved ZVT Boost Converter is verified by the analysis of the simulation waveforms and experimental waveforms.The Boost converter avoids the occurrence of sneak circuit phenomena and realizes the soft switch working process of all switching devices.