The Research Of Micro-Plasma Arc Welding Transistor Power Source

Micro-plasma arc welding is a welding method of high temperature, high energy density, high ionization. It has the feathers of compressed arc,concentrated energy and it is suitable for welding thin pieces. It is widely used when the device parts are more and more sophisticated and small day by day. Micro-plasma arc welding technology has been paid more and more attention in the field of precision machining of thin-walled parts.Its welding current is less than 30A.The stability of welding in low current is the most important factor in micro-plasma arc welding technology. Welding in low current is one of the most notable feathers of micro-plasma arc welding. It still can weld when the current is as low as 0.05A. Maintaining a stable welding arc when welding in low current requires a high standard welding power source. The characteristics of micro-plasma arc welding power source directly influence the quality of welding technology.In this paper, the main circuit of micro-plasma arc welding transistor power source has been designed, including the main circuit transformer design and the transistor group,filter capacitor,filter inductor,rectifier's selection and design. Meanwhile,the feedback control circuit unit and central processing circuit unit with DSP+CPLD of micro-plasma arc welding power has been made. Feedback control circuit unit effectively affect the power source's closed-loop control through sampling,amplification,given and the integral operation, then it makes the micro-plasma welding equipment have the precise welding current output.The central processing circuit unit with DSP+CPLD of micro-plasma arc welding not only realizes the control of welding characteristics, such as arc starting,arc ending,arc transferring but also the On-Off control of water and gas circuit.Micro-plasma arc welding power'display,input,precision given of sampling feedback control circuit and other links have also been successfully achieved. Micro-plasma arc welding power source with transistor has been simulated and studied with saber software in this paper. The main power circuit and feedback controller of micro-plasma arc welding power source have been modeled, meanwhile the power's characteristics including the main circuit 'open-loop characteristics,the closed-loop characteristics of the power and the ripple in the output current have been simulated and analyzed. A preliminary discussion on the stability of the power with low current has also been made in this paper. Micro-plasma arc welding power source with transistor has been studied in this paper. Meanwhile, the inverter welding power source has also been simulated and studied. At last, this paper also makes a comparison between the linear amplifier power with transistors and the inverter power on its characteristics.