| The pulsed power supply system based on Lead-acid batteries for the45T flat-toppulsed magnet is under construction at WHMFC, and a kind of rapid, reliable, long-life andhigh-power DC switch is necessary for its reliable operation. This paper gives thedevelopment of a35kA DC thyristor switch based on the requirement of the power supplysystem. The details as follows:The circuit schematic and working principle of the DC thyristor switch which usesforced commutation technology to turn off the main switch is proposed and analyzed.Based on the analysis of the turn-off process and the derivation of the reliable turn-offcriterion, the structure of a35kA DC Thyristor switch system and its parameters arecarefully designed to meet the requirement of the power supply. To guarantee reliability ofthe switch, effective measures are adopted to realize balanced current distribution in theparallel thyristors; and protection measures of the thyristors under different faultyconditions are fully discussed.The working principle of the35kA DC thyristor switch is simulated and analyzed byusing MATLAB-Simulink. The models of the switch, the pulsed magnet, and the thyristortemperature rise are built. The time variations of current, voltage, temperature rise areanalyzed, and the transient turn-off process of the switch is particularly studied. Thesimulation shows that the switch can turn off35kA direct current rapidly and reliably.At present the manufacturing and assembling of the switch has been completed, andthe switch is under comprehensive test. The test results show that the switch can meet therequirement of the power supply system, and will be used in45T flat-top pulsed magnet forsome special science experiments. |
PDF Full Text Request