Study On Effects Of RSD Pre-charge Upon The Maximum Turn-on Voltage

Reversely Switched Dynistor(RSD) is a novel high-power high-speed semiconductorswitch. With the characteristics of high forward blocking voltage, strong current capacity,high converting speed, long lifetime and high repetition rate, RSD has a great prospect in thehigh-voltage high-current pulsed power field.The turn-on process of RSD is composed of the reverse pre-charging and the forwardconducting. During the forward conducting process, the turn-on voltage of RSD will occur ashort-term peak, which is called the maximum turn-on voltage. The maximum turn-onvoltage of RSD is a very important parameter, the reduction of which can help lower RSDpower consumption, and further reduce the device working temperature, extend the life ofRSD and promote the application of the device. Therefore studying the effects upon themaximum turn-on voltage is of great significance.Previous experimental studies have found that within a certain range, corresponding to acertain degree of pre-charge time, greater pre-charge current causes greater pre-chargeamount, thus leads to smaller maximum turn-on voltage of RSD. On this basis, the effect ofRSD pre-charge duration upon the maximum turn-on voltage corresponding to a certainpre-charge amount is studied in this paper. First, the model of Grekhov turn-on voltage isderived from the theory of power semiconductor device and the converting principle ofcontrollable plasma layer. Then the detail of the turn-on mechanism of RSD is analysedthrough the experiment of RSD direct pre-charge circuit. Based on these results, an viableexperiment project of RSD turn-on circuit is designed. Experiments show that at certainpre-charge amount, as pre-charge duration grows, the maximum turn-on voltage of RSD firstdecreases and then increases. Finally, the concept of effective pre-charge amount, theremaining portion of the charge from the whole charge streamed by pre-charge current minus the consumption due to the recombination effect of large injection, is proposed in this paper,which gives an explanation for the results of the experiment.The minimum value of RSD maximum turn-on voltage corresponds to the maximumvalue of effective pre-charge amount, which suggests that the circuit parameters in practicalapplication of RSD can be adjusted through experiment project of RSD turn-on circuitdesigned in this paper to make RSD work under this pre-charge time circumstance, so thatthe circuit performance can be improved and the low-power turn-on circuit design of RSDpulsed power system can be realized.