Analysis And Design Of High-Power Intrinsic Safe Forward Converter

With the development of coal mine automation,the output power of the anti explosion power supply applied to the coal mine is urgently needed.However,the existing safety proof measures and the intrinsic safety evaluation methods restrict the further improvement of the output power of the intrinsic safety.Therefore,the design of the high power essential safety switch converter is designed on the basis of Power-i technology.And evaluation methods have important theoretical significance and engineering application value.In this paper,the combustion and explosion process of flammable gas caused by electric spark is described from the angle of thermal ignition,and the principle of realizing high power output by Power-i technology to suppress the spark discharge energy of switching power supply is analyzed,as well as the composition of the power supply system and its evaluation method.On the basis of the analysis of the principle and work characteristics of the various switch topology,the forward converter is selected as the topology of the high-power local security power supply.The critical state and working mode of forward converter are studied in depth,and the working state of the forward converter in the full dynamic range is simulated by Saber software.The simulation results agree with the theoretical analysis that the maximum of the maximum input voltage and the hourly load resistor is the maximum of the inductance current and the output voltage.According to the technical index of Power-i system,the circuit structure of high power intrinsic safe converter is put forward,and the double protection circuit of overcurrent,overvoltage and short circuit when the output is short circuited and open fault is designed.According to the requirements of coal mine automation,a self recovery circuit composed of monostable trigger is designed to ensure that the converter can automatically recover the normal working state after the fault is relieved.The main components in the power loop,such as high frequency transformer,input rectifying bridge and filter capacitor,output energy storage filter LC,switch tube and side diode are analyzed,and the theoretical basis of device selection and parameter design is obtained.According to the Power-i standard,the high power intrinsic safe forward converter was produced,and the power response time,the evaluation coefficient and the transient pulse test were carried out.The experimental results of an explosive safety spark experiment on the prototype have been carried out,and the experimental results verify the intrinsic safety of the designed high power intrinsic positive shock converter,and reflect the correctness of the theoretical analysis and design method.