A fast dynamic discharge power supply for long pulse neutral beam injector

The paper presents the design and performance of the discharge power supply for the ion source of the long pulse neutral beam injector. The dc output is 10-160 V, 100 A (max.) with peak ripple less than 400 mV at rated load. Long term stability is better than 0.1% with very fast turn on time (20 μs) and turn off time (2 μs). Settling time is less than 40 ms to ±2% of final value. 24 such power supplies are used for one ion source. The control is matched to meet the discharge dynamics. The design uses novel features in power electronics, these are discussed and performance results are presented.