| Micro-hollow cathode discharge (MHCD) is a newly advanced micro-discharge technique based on ordinary cathode discharge in a sub-millimeter scale micro-hollow under high pressure. MHCD can be used as plasma cathodes for the large-volume high-pressure glow discharge to overcome the instability of glow discharge.At first,the summary of research and development of MHCD is presented.And then,on the basis of the MHCD experiments, the switching power supply which can control the gas discharge mode of MHCD (cw /pulse) and adjusts the output is designed. In this paper , a control theory of FB ZVS-PWM switching power supply , the choice of scheme and the design of frame and component parameters of the main circuit ,assistant circuit and control circuit are discussed. In the design of the power supply, the main circuit topology frame uses full-bridge series resonant switching and parallel load connection, in which, four MOSFETs are adopted as the power switches, and by four pulses which UC3879 produces, high frequency operation and fast response are realized. In addition, the MOSFET in the switching power supply has no hard turn-on or turn-off situation in transition, thus the disturbance to the power system is avoided. Especially,by the use of high frequency transformer, PQ50/50, the switching power system can provide the steady discharge current without any amperite. |
