SOLIDSTATESPARKGAP REPLACEMENT SWITCHES

ofonethyristor causes thevoltage drop across ittobegin Improvements insolid state highvoltage switching tofall, andthevoltage dropacross theother devices to technology nowmakesitfeasible toreplace triggered rise. Thisresults inacurrent flowing through thesnubber sparkgap switches, usedin many medicaland circuits tocharge thesnubber capacitors. Thiscurrent commercial applications toswitch tensofkilovolts and flowsfromtheexternal circuit whichsupplies the thousands ofamperes, withcompact solid state switches. required energy. Because thecapacitance ofthesnubber Thesolid state switch wehavedeveloped istriggered bya capacitors issmall, this energy isaverysmall fraction of single 10V isolated trigger pulse toonlyonestage ofa thetotal switched energy. Using atransformer, aportion multi-staged highvoltage solid state switch, therebyofthesnubber current iscoupled tothegates ofthe reducing thesizeand decreasing thetriggering thyristors, triggering thethyristors. Thethyristor stages complexity oftheswitch. Theswitch usessmall 5300V areconnected inseries andexperience thesamesnubber thyristors capable of14kApeakcurrents and>25kA/ts current, resulting insimultaneous turn-on ofallthese rateofcurrent risetimes. Theshort turn-on delay, lessstages. Thecomponents usedtoinitiate triggering ofeach than200ns,makestheswitch suitable forcrowbarstage areatthepotential ofthatstage sothat nohigh applications. voltage isolation isrequired. Thismakesforacompact, Thispaper will include adescription ofthesolid stateinexpensive triggering system enabling thyristor stages to switch andtriggering system aswellasshowdatafroma bestacked inseries tocreate veryhigh voltage switches. 24kVsystem using boththespark gapandthesolid state replacement switch todischarge a0.15iFcapacitor at1.5Switch Current versus Time using aSpark Gap Switch and a6Stage Solid State Spark Gap pps . The switchcurrenthas a ringing dischargewitha Replacement Switch, 0.15 p FCapacitor charged to22.5kV