Development of 3 MW dual output high voltage power supply for ICRH system

Abstract

High voltage power supply (HVPS) based on pulse step modulation (PSM) topology has already demonstrated its ability for broadcast transmitters, accelerators using radio frequency (RF) source and neutral beam injectors. Typical ion cyclotron resonant heating (ICRH) system composed of cascaded connection of driver stage and end stage would need two power supplies. A novel concept of tapping two outputs from single PSM based HVPS is attempted for the first time. A PSM based HVPS is developed with dual output to feed driver and end stages of a high power RF amplifier. This article discusses the development of a HVPS, capable to provide 14–18 kV, 250 kW to driver stage and 16–27 kV, 175–105 A, 2800 kW to end stage RF amplifier chain. Here dual output are controlled independently by single FPGA based PXI controller which support all pros of PSM based HVPS like low ripple, fast dynamics and very short time to turn-off. Discussed HVPS supports non-linear demand from ICRH system i.e. lower current (105 A) at higher voltage (27 kV) and higher current (175 A) at lower voltage (18 kV), which developed as indoor compact solution. As an add-on specification, HVPS facilitates 1 kHz RF power modulation. The HVPS is composed of two cast resin multi-secondary transformers (CRT), 48 numbers of switched power supply (SPS) modules; FPGA/real time based controller and other auxiliaries including passive protection devices. Present article describes technical details of HVPS components which are manufactured to IEC standards. HVPS with dual output is an effective replacement to conventional solutions, as it offers optimized solution for equipment bulk as well as economy.