High-voltage power supply for ECRH system on J-TEXT Tokamak

A 100kV/60A high-voltage power supply (HVPS) has been established to energize the electron cyclotron resonance heating (ECRH) system for J-TEXT tokamak. With the pulse step modulation (PSM) technology, the HVPS has many advantages, especially the low stored energy and short protective time in case of short-circuit fault. This paper gives a description and key design features for the isolated transformers, switch power supplies (SPS) modules, measurement equipments and controller. In this HVPS, 4 dry-type transformers with 36 secondary-windings drive the 144 series SPS modules and isolate the high voltage between the rectifiers and the 6.3kV AC bus. A controller based on the 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 responses any over current fault in less than 5 μs. Moreover, to acquire better dynamic response and stability, a control strategy improved from the conventional PWM phase-shift modulation method has been proposed. The experimental results are also presented and show that the power supply system performing good.