High-voltage, high-power, pulse-step modulators for the accurate supply of gyrotron and other heating devices

At the Max-Planck-Institut fur Plasmaphysik in Greifswald, Germany, there are planed several plasma heating systems with high output power. There is on the one hand an ion cyclotron resonance heating (ICRH) with a pulsed output power of 2 MW per RF amplifier, a neutral beam injection (NBI) with a pulsed output power of up to 3 MW per accelerator and an electron cyclotron resonance heating system (ECRH) with totally 10 MW output cw with 10 tubes. For the supply of the different systems universal high voltage power sources with totally 26 MW electrical power in cw operation and 52 MW in pulsed operation are under construction. The output voltage can be adjusted up to 130 kV. The system has very low amount of stored energy. For this reason a commonly used crowbar system Is not necessary. The power supplies have the capability of modulation up to 500 Hz square wave with a modulation degree of one and several kHz with lower degrees. To meet all requirements for all the heating systems, the supply can be configured concerning polarity, maximum voltage and current, modulation parameters, series operation, pulse length supervision etc. The supply comes in four units where the first unit with 6.5 MW cw is in operation since end of 2001.