Improve the reliability of the ion source beam extraction by adopting a solid-state suppress electron power supply

A solid-state suppress grid power supply (SGPS) is developed to be applied to the 5 MW level neutral beam injection (NBI) on HL-2M Tokamak. The power supply consists of ten modules in series, with an index of 560 V/40 A. Each of the modules is composed of an isolated transformer, rectifier, filter tank, insulated gate bipolar transistor switch, gate-drive circuit, free-wheeling diode, and so forth. An embedded system STM32F103 is used for controlling and protecting the SGPS. Meanwhile, the transient output capacity of the SGPS is tested. The effect of the output voltage of the SGPS on the extracted beam current is studied. The experimental results show that there is a turning point in the relationship between the suppress voltage and the extracted beam current. When the rate of the absolute value of the suppress voltage and the gradient voltage is more than 2.5%, the efficiency of the extracted beam of the ion source can be improved. Compared with the previous types of equipment of the NBI system, the extracted beam success rate of the new SGPS increased by more than 20%. The SGPS meets the requirements of the NBI system.