Research On Intrinsically Safe Active Clamp Flyback Converter

Due to the wide application of industrial IoT technology,the degree of automation of underground mining in coal mines is getting higher and higher.As the power supply core of many automation equipments,the power supply is very important for the safety production of coal mines.Therefore,the underground power supply must have explosion-proof function.At present,among many explosion-proof methods,the explosion-proof performance of intrinsically safe power supply is the best.Therefore,in order to improve efficiency and reduce volume,this paper studies the intrinsically safe active clamp flyback converter.First,through the analysis of the protection method,the back-end cut-off protection structure are selected.By analyzing the working principle of the active clamp flyback topology,the necessary conditions to achieve its zero voltage switching,the energy transmission process,and the output short-circuit release energy are derived.According to the minimum ignition curve of the simple capacitor circuit in GB3836.4,the non-explosion evaluation criterion of its output intrinsic safety performance is given from the perspective of the minimum ignition energy.Then,the power circuit and protection circuit of the output intrinsically safe active clamp flyback converter are designed.Through its equivalent circuit diagram,its transfer function are derived,and its amplitude frequency characteristics are analyzed.Based on this,the feedback circuit are designed.The simulation and prototype experiments show that the main power switch and auxiliary switch can achieve zero voltage switching,and other performance can also reach the design index.According to the non-explosive evaluation criterion,the prototype meets the requirements of output intrinsic safety,which proves the correctness of theoretical analysis and design.In view of the fact that the traditional active clamp flyback converter need to add additional leakage inductance and the secondary rectifier can not realize zero current switching,this paper analyzes and designs the critical conduction mode active clamp flyback converter.Through the simulation and experimental prototype verification,the zero voltage switching of the original side power switch and the zero current switching of the secondary side rectifier are realized,which proves the consistency between the theory and the experiment.There are 119 figures,and 78 references in this dissertation.