Study On The Performance Characteristics Of The Triggering System Of Gas Spark Switch

The main output switch is one of the key components in SG-III power conditioning module. It's operating characteristics directly determine whether the power conditioning module can provide the right pulse current for the xenon lamp load, and whether the energy module can work steady. The output switch is a spark gap, of which two electrodes are made of high density graphite, and the reliability of its working is largely determined by the stability of trigger system. The research object in this thesis is the performance characteristic of trigger system for the gas spark switch.This thesis initiates with the the background of this research, and introduce the recent development trend of pulse trigger generator and Marx generator at home and abroad. Describing the composition of trigger system, icluding Marx generator and magnetic switch. The structural features of gas spark switch and the basic principles of Marx generator and magnetic switch are briefly discussed. The trigger needs of switch are preliminary analysised by analysising the breakdown mechanism of air gap in nanosecond pulse.By measuring the trigger voltage Marx generator added on the negative electrode of gas switch under different working conditions using water resistor divider to analyz the requirements of trigger voltage for the gas switch. The research found that the breakdown voltage and delay time are larger when the air pressure increased, but the trend of the breakdown voltage is not completely synchronized in the charging voltage of the capacitor. Through theoretical analysis of the experimental results, combined with the static characteristic of the gas switch, determine the air pressure of gas switch is 130kPa. On this pressure the breakdown voltage is 104.4kV, delay time is 35ns, so the output of Marx generator can meet the requirements of voltage opening characteristics of the gas switch. There is a period of time between gas switch being triggered by Marx generator and main discharging current formation. During that time period, trigger current played a significant role. Equivalent Peterson circuit explained the trigger current have much to do with the second stage of breakdown of gas switch , because spark resistance will have a rapid decline. Radius is inversely proportional to spark resistance, so smaller spark resistance is propitious to the formation of discharging current. In this thesis, explan the certain influence of trigger resistance on the stability of the trigger gap breakdown by the size of simulation∫i2dt.The magnetic switch material select Iron-based nanocrystalline soft magnetic alloys because its properties of High saturation magnetic induction, high magnetic permeability and properties of nano-materials. By introducing some important physical quantities, their calculation methods and designing some experimen for magnetic core, the isolation characteristics of the magnetic switch is analyzed in detail. By analyzing the results obtained, and the engineering requirements, bring up the saturation inductance of magnetic switch is less than 1μH, and unsaturated inductance more than 20μH, and designed a magnetic switch superposed by three magnetic core which outside diameter is 90mm, inner diameter is 30mm, and height is 80mm. From the experimen in the energy module, found the back contact of magnetic switch is 20kV,which meeting the needs of the trigger isolation.