Overview of 100-kV/60-A High-Voltage Power Supply Utilized for the ECRH System on J-TEXT Tokamak

A 100-kV/60-A high-voltage power supply (HVPS) has been established to energize the electron cyclotron resonance heating system for the J-TEXT tokamak. The HVPS based on the pulse step modulation technique has many advantages, including low stored energy and short protective time in case of a short circuit fault. This paper describes and provides the key design features of isolated transformers, switch power supply (SPS) modules, measurement equipment, and controllers. In this HVPS, four dry-type transformers with 36 secondary windings drive the 144 series SPS modules and isolate the high voltage between the rectifiers and the 6.3-kV ac bus. A controller based on PXI technology, which conforms to the ITER CODAC standard, has been developed to operate the series switches in each SPS module. The error signals from all the modules are monitored by the controller, and the fast protection responds to any current fault in <;5 μs. A control strategy improved from the conventional pulsewidth modulation phase-shift modulation method has also been proposed to acquire better dynamic response and stability. Experimental results show that the power supply system performs well.