Design of the control system of acceleration grid power supply for CFETR N-NBI prototype

In order to realize the 200 keV negative-ion-based neutral beam injector (N-NBI) prototype of China Fusion Engineering Test Reactor, an acceleration grid power supply (AGPS) is under development. Adopting a single stage inverter type topology, the AGPS is rated at 200 kV/25A for 3600 s. Here, the paper presents a distributed control system based on PCI extensions for instrumentation (PXI) and field programmable gate array (FPGA) technology, which can fulfill the high requirements in terms of the control strategy, malfunction protection, integration with the upper control system and real-time monitoring, highlighting the operation sequence both in normal and abnormal scenarios. In addition, a 10 kV/6A AGPS prototype has been realized to verify the control system. The distributed control system can respond to the interlock signal from the upper controller within 2 μs while disabling the inverter within 20 μs in case of an abnormal current or voltage output status.