Study On The Microbeam Plasma Arc Welding Power Source Study Of Chopper Control

Micro-plasma arc is a compressive arc sprayed by approximate0.8mm channelnozzle aperture, it has the energy concentrated, high energy density, big arc characteristicsand so on. Therefore, micro-plasma arc welding in thin pieces and precision parts is animportant welding technology in welding fields.Micro-plasma arc welding system is mainly composed of the power system, controlsystem, welding torch, etc. In terms of arc welding arc welding power and controltechnology. At present, the thyristor rectifier control and the inverter type arc weldingpower source is widely used. This paper studies a new type of arc welding power ofchopper control, which appling to the micro-plasma arc welding system.Micro-plasma arc welding system is composed of the non-transferred type plasma arcwelding power source and transfer of plasma arc power supply system. Power system ismainly composed of the electric power system, pulse width control system, drive circuitand program control system. Power circuit system adopted chopping control technology,appling the MOSFET as the chopper switching device control power output characteristics.In order to achieve the requirements of the power system output power,it utlizes powerMOSFET device in parallel, output characteristic of the output current negative feedbackand PI control technology is controlled by pulse width modulation (PWM) technology.Using pulse width modulation (PWM) and switch technology set pulse output currentmodulation technology.The switch operating frequency of chopper control adopting MOSFET power deviceis set to53.763kHz. Current feedback is finished by lime current transform device. Itutilizes pulse width modulation integration device SG3525. Output current negativefeedback and PI control achieves requirements of steep fall in external characteristic anddynamic performance. This design of the transfer type plasma arc welding power suppliesoutput current adjustment range1~16A, the non-transferred type plasma arc weldingpower source output current fixed for3A, it meets the micro-plasma arc welding. That transfer of plasma arc power system suppling pulse frequency of output current up to1162hz is a very high for output current pulse frequency about data.Welding test for stainless steel plate welding, through observation of weld joint andwelding process shows that chopper control micro-plasma arc welding machine hasreliable the process that is on stable welding process and the process welding arc startingwelding, arc closing. The chopper control on micro-plasma arc welding system is feasible.