Research On Discharge Characteristics Of Output Intrinsically Safe EC Circuit And Non Explosive Intrinsically Safe Evaluation

Existing capacitive circuit models in the field of intrinsic safety generally ignore the effect of the power supply on the energy storage element and the sparkover during discharge.For output intrinsically safe switching power supplies,the secondary side rectified output terminals are usually directly parallel with larger filtering capacitors.During discharge,the energy provided by the power supply can not be ignored,so the existing capacitive circuit model is no longer suitable.Exploring non-explosive intrinsic safety characteristics of evaluation methods to facilitate designers in the development process to predict the intrinsic safety circuit performance,provide guidance for the circuit design,shorten the development cycle.In this thesis,based on the typical experimental waveform,it is found that the cutoff EC circuit spark discharge waveform has a direct interception characteristics.Based on the experimental data of IEC spark test device,the equivalent circuit model of cutoff EC circuit was established and the corresponding mathematical model was deduced.The mathematical model and numerical simulation tools were used to study the influence of the critical parameters of cut-off EC circuit on the safety performance of spark discharge.In this thesis,according to the voltage transient drop to determine whether the spark discharge,according to the current rate of change di/dt to determine whether the arc discharge,to achieve precise fault identification.Based on the principle analysis and circuit design of the output intrinsically safe circuit,and the code design and algorithm realization,the hardware test platform of spark test is set up and the relevant comparative experiments are completed to verify the correctness of the mathematical model of the cut-off EC circuit.In this thesis,the Buck converter is taken as an example to derive the constraint of the electrical parameters of the converter.Based on this,the energy released by the discharge gap under the most dangerous condition of Buck converter is analyzed.Combined with the switching converter test experiment and the national standard GB3836.4-2010 moment of transient allowable transient energy rating,the non explosive intrinsic safety characteristics of switching converters are evaluated.