Design and development of the star-point control high voltage power supply of the ECRH system on HL-2A tokamak

Abstract

To supply the cathode high voltage for the four gyrotrons ( 68GHz/500kW/ls) of the ECRH system on HL-2A, the star-point control high voltage power supply ( HVPS) with rated output of60kV/120A has been built. The filtering inductors in the HVPS are on the primary side of the rectifier transformers, so the required insulation level of the inductors to local earth is much smaller than that they are on the secondary side of the rectifier transformers. The output voltage can be modulated by changing the excitation current of the rectifier transformers. The high voltage pulse modulators based on tetrode vacuum tube ( TM-703FB) are also applied in the power supply to realize the fast rising and falling of the output voltage. The over-current protection and voltage overshoot are executed by the star-point

The Development of the High-Voltage Modulators Based on TM703FB Vacuum Tube for Auxiliary Heating on HL-2A

“…By controlling the modulator, the turn-on and turn-off of the high voltage is fast , it can meet the demand of auxiliary experiment , and the modulator is successful to output high voltage high power in 1 second. [3] Figure 4. The output waveforms of the modulator…”