Research On Grid And Cathode Circuit Of Tube In High Power RF Laser Power Supply

High power electronic tube is the core component of the self-excited RF laser power supply. The power supply is determined by the tube filament current, grid current and cooling system. This thesis aims at researching on circuit properties of the grid and the cathode for engineering application. The main contents of the thesis are as follows:(1) The whole structure and function of the RF power supply have been analyzed. High- precision, high-stability and big-current filament transformer has been designed, it provides a stable current source for the tube filament.(2) High-precision filament steady current system has been designed. According to the requirement for the stability and the adjustability of the filament current, the steady current plate that can control the measurement of the filament current has been designed by adjusting the voltage at the primary side of the filament transformer. The output voltage of the SRC can be arranged from 300V to 380V according to the principle that the output voltage of the SRC is determined by the control signal. The control signal uses PID to make sure that the control signal equals the given signal, to make the control signal adjustable.(3) The characteristics of the components in the grid of the electronic tube have been studied. According to the requirements of the current and signal filter in the grid, the current-limiting resistance, the signal filtering inductance and the protecting circuit have been designed. The result of the filtering inductor has been simulated by PSpice.(4) A cooling system has been designed for the electronic tube. The air-cooling and water-cooling systems have been designed by analyzing on the heat loss of the electronic tube. The air-cooling system is employed for the peripheral circuit and the water-cooling system is used for the interior. In the water cooling system, the impact of water quality on the RF power supply also has been analyzed.The quality and stability of high RF power supply which this thesis developed directly affects the output laser power and beam quality of the RF slab CO₂ laser.