Research on Short-Circuit Discharge Behavior of Capacitive Circuits Based on Safety Spark Test Apparatus

Based on the safety spark test apparatus, the Short-Circuit Spark Discharge (SCSD) behavior of the simple capacitive circuit and switching converter are studied. It is pointed out that their SCSD process can be divided into four stages, i.e., dielectric-breakdown stage, spark-generated stage, spark-maintenance stage and spark-extinguish stage. For the simple capacitive circuit, its spark resistance is larger and maintaining voltage is almost unchanged in the spark-maintenance stage. As for the switching converter, its output short-circuit characteristics depend strongly on the load resistance and its maintaining voltage decline rapidly with the decrease of the load resistance. The experimental results also show that the discharge duration is approximately linear relationship with the capacitance and unrelated to the initial voltage. The circuit model is proposed, which can simulate the output SCSD process of the switching converter. By using the least-squares method, the relationship expressions between the discharging duration and capacitance in each time-stage are derived and the corresponding equivalent-resistance is obtained. The mathematical models of simulating the SCSD process of the switching converter are proposed, and the expressions of the current and voltage are derived. Experiment and simulation results are in positive to the analysis showing the feasibility of the proposed models.