Design of a High-Power Radio Frequency Ion Source Reflection Protection System

[Background]: Due to the lack of filament lifespan limitations and electrode contamination, the high-power radio frequency (RF) ion source is the most promising ion source for achieving steady-state operation in neutral beam injection system research. During the operation of the RF ion source, dynamic variations in plasma impedance can increase reflected power, reduce RF coupling efficiency, and, in severe cases, damage core components. [Purpose]: The study aims to design a reflection protection system to address impedance mismatch and reflected power spikes in the high-power RF ion source. [Methods]: The system, based on a microcontroller, monitors reflected power in real-time using a high-precision ADC, integrates reflected power protection and spike pulse shielding functions, and achieves fast response through interrupts. A remote monitoring interface was designed using LabVIEW to enable parameter adjustment and data storage. [Results]: The test results demonstrated that the system has a maximum response delay of 150μs for protection signal output, with the spike shielding time adjustable between 10ms and 10s and 1ms precision, meeting real-time operational requirements.

[Conclusions]: The proposed system ensures safe and stable operation of the high-power RF ion source, while also offering advantages such as high cost-effectiveness and easy maintenance.