Design, development, testing and operation of Regulated High Voltage power Supplies (RHVPS) utilized by NBI and RF heating systems for SST1

• Main Authors: Patel, P. J., Sumod, C. B., Thakkar, D. P., Gupta, L. N., Patel, V. B., Bansal, L. K., Qureshi, K., Vadher, V., Singh, N. P., Baruah, U. K.
• Format: Conference Proceeding
• Language: English
• Subjects: Heating; IGBTL; Multisecondary transformers; Optical fiber amplifiers; Pulse step modulation; RHVPS; Switches
• ISSN: 1078-8891
• DOI: 10.1109/SOFE.2011.6052332

Regulated High Voltage Power Supplies (RHVPS) are major components of any high power heating and current drive system for a Tokomak. A typical RHVPS need to have fast dynamics, good ripple and regulation performance and most importantly μS order fault clearing time. The development of a series of RHVPS ranging from 14 kV to 100 kV and several MW power to be used for the RF and NB heating systems of the SST-1 Tokomak and results thereof are presented here. Extensive tests on an 80kV, 75A power supply were done and the RHVPS is regularly used on a Neutral Beam Injector. The system uses the pulse step modulation technique for control of the series switches of each switched power module fed from multi-secondary transformer. A special switching transition matrix controls the series switches with which the rise/fall slope control could be programmed from few μS to hundreds of m Sec range. The fast protection clears any over current fault in less than 2 μS; fault energy has been measured to be less than 5 Joules. Apart from the major features of the system, the presentation describes some studies from fault conditions of the system and mitigations thereof.