Design And Implementation Of Bias Power System For Electron Injection On J-TEXT Tokamak

Low loop voltage start-up can reduce voltsecond for heating field on Tokamak andextend plasma discharge duration, which plays a very important role in Tokamak plasmaconstraints. The idea of E×B electron injection is first put forwarded by professor PanYuan in1994,which is aimed to inject electrons into plasma, the experiments on HT-6Mhave proved it is feasible. In2009, J-TEXT has ready for a deeper electronic injection inHuazhong University of Science and Technology. Bias power supply is used to providean electric field for electrostatic drift and real-time feedback tracking plasma voltage,which plays a very important role during electronic injection experiments.According to the E×B electron injection power supply requirement, Bias powersupply was based on TMS320F2812for the voltage PID feedback controller and bridgeBuck topology is an important key in the main circui, realize-800-800V DC voltageoutput,500mA-3A current output, the output ripple is less than1%.Through analyzing Bias power supply operation process and working principle,theprinciple and application of DC transformer, AC small signal and State space averageanalysis are studied to bulid AC small signal analytical model in steady-state voltageoutput, deduce bias transfer function. Base on bias operation analysis and the transferfunction, PID controller design and PID parameters adjustment principle are discussed indetail. After the PID controller parameters, the bias closed loop simulation circuit verifiedthe feasibility of the system.Base on TMS320F2812as the core of Bias control system, AD7606and AD5724related peripheral circuit are designed. Meanwhile, bias PCB was drawn and controllerhardware system design was completed. Experimental platform test results shows thatKp=0.07,Ki=0.01,Kd=0.09, Bias power supply can get smaller rise time, overshoot, thesmall ripple in transient response and steady performance, can achieve design effect.