Comparison of Magnetic Field Characteristics Produced by Three-Electrode Spark Gap Switch and Thyristor Switch in Power Pulsed Systems

Spark gap switches with three electrodes and thyristor switches were used in the pulsed power supply system of the electromagnetic launcher. Electromagnetic field radiation from switches could cause electromagnetic interference damage to the devices. In order to analyze the problem, electromagnetic field radiation waveforms around two typical switches were measured by the B-dot. Based on the wavelet analysis method, time-frequency characteristics of the radiation field are compared for the two types of switches. The results represent that the maximum frequency of the thyristor switches' signal is much lower than that of the spark gap switches' signal, according to the frequency distribution. The turn-on time of the spark gap from the initial triggering time to the main discharge time is 0.024 ms'C and the variation is limited to less than 0.008 ms. The maximum frequency duration is about 0.005 ms, and the variation is limited to less than 0.003 ms. The maximum signal amplitude of thyristor switches is lower than that of spark gap switches. The comparison and results will benefit the compatibility design of the system.