文档介绍：Abstract
Title: RESEARCH ON CONSTANT CURRENT CONTROL STRATEGY OF RON SPUTTERING POWER SUPPLY
Major:Power Electronics and Power Drives
Name:Chunqiang LIU Signature:
Supervisor:Prof. Qiang SUN Signature: Guitao CHEN Signature:
Abstract
With the increasing demand of new materials, especially in the continuous improvement of wear resistance, heat resistance and other requirement, plasma processing is used widely in the field of material surface treatment. The process raises higher demands for power supply. Improving the anti-disturbance and load adaptability of the power supply has e the main research direction.
Firstly, the circuit model of plasma load was introduced. The current controller was designed by frequency domain method, and the discrete methods of bilinear transformation and pole-zero matching pared. The influence mechanism of output admittance on the load disturbance was discussed. Then, the output voltage feedforward based on plasma load equivalent circuit model was introduced to the current loop. The output voltage pensation function was deduced to reduce the output admittance, and the influence of plasma equivalent load model parameters on feedforward functions was analyzed. Comparisons between the control with and without voltage pensation had been presented. The output voltage feedforward control was verified on the ron sputtering power experimental platform. Experimental results show that, the proposed control strategy not only effectively restrains the influence of load disturbance on constant current source, but also improves the system dynamic response.
Then, in order to solve PI control saturation problem when power supply transformed from no-load to load, the voltage and current switching control was adopted. Using hysteresis loop control mode, no-load voltage control was achieved. No-load to load response curves under current loop PI control and voltage and current loop switching control were presented. A up protection program was given