Design of the soft-start resistance in PSM high voltage power supply for ECRH

Abstract The soft-start resistance plays an important role in high voltage power supply (HVPS) based on pulse step modulation (PSM) for ECRH on EAST, which is fusion experimental device for total superconducting tokamak in china, and has a great influence on the transient process of system operation. Reasonable selection of the soft-start resistance can guarantee the stability of the circuit and ensure that the device withstands maximum voltage and current. So the response process is analysed detailedly by proposing DC equivalent circuit model, and the process analysis and performance comparison are given under the conditions of different soft-start resistance parameters. At last the theoretical analysis is proved by simplorer simulations. The soft-start resistance is designed for the HVPS of 140 GHz ECRH system for a smooth charging without overshoot of the capacitance, and the final experimental results show that it is in agreement with the theoretical analysis and is stable and reliable to the power devices.