Neutral Beam Power System for Fast Grid Modulation*

Neutral beam injection (NBI) is an important tool for plasma heating, current drive and a diagnostic at fusion science experiments around the United States. Producing power systems that can respond rapidly (10 µs) at high voltage (10 to 100 kV) for beam acceleration or high currents (~ 1 to 5 kA) for control of the ion source is non-trivial. Currently, there are no vendors in the United States for NBI power systems. Eagle Harbor Technologies (EHT), Inc. is developing new solid-state switching power systems for NBI that takes advantage of the latest developments in solid-state switching. EHT has developed a series resonant converter that can be scaled to the power required for NBI at small-scale validation platform experiments. This power system can modulate the injection beam current during a plasma shot, which can lead to improved control over the plasma. Additionally, these modern solid-state supplies can be made smaller and lower cost that previous generations of NBI power systems. We will present the Phase I testing results, including demonstration of current modulation on a neutral beam system.