The Study Of Integrated Pulsed Tandem MIG Arc-welding Power Source

The Integrated Pulsed Tandem MIG Arc-Welding Power Source is a part of the high-efficiency welding,because it provides a controlling method and power to high-efficiency welding.The Integrated Pulsed Tandem MIG Arc-Welding Power Source combines DSP to controlling process,conducting to more functions,better controlling precision,higher parameter stability,more stable power output and higher welding quality,compared to analog controlling mode.Welding products have been required to be both high quality and high efficiency,and practical applying and producing can be able to meet the requirements.This paper summarizes some controlling methods and welding equipments providing high-quality and high-efficiency welding at home and abroad,and designs an Integrated Pulsed Tandem MIG Arc-Welding Power Source.The Integrated Pulsed Tandem MIG Arc-Welding Power Source has IGBT full-bridge soft-switch inverter,DSP(TMS320F2812)controlling system and man-machine conversation system based on MCU(STC89C58RD+).Under the control of DSP+MCU,the welding power source can realize digital control and output high-precision external characteristic.Firstly,this paper makes a brief description of IGBT full-bridge soft-switch inverter,and soft-switch inverter working process.A detailed description of controlling system circuits is provided.The circuits contain DSP controlling system circuit,driving system circuit and man-machine conversation circuit.DSP controlling system circuit,containing DSP minimum system,sampling circuit,AD correcting circuit and protecting circuit,monitors the main welding process.DSP controlling system receives,processes and sends data to control the power output.Driving system uses current-type pulse-width-modulation device UC3846 and two 555 chips to output PWM signals.The PWM signals are amplified by pulsing transformer to drive IGBT inverter.Man-machine conversation system uses MCU(STC89C58RD+)as controlling core and contains parameters presetting circuit,displaying circuit,encoder regulating circuit and communicating circuit.Man-machine conversation system has the main function to preset and display parameters.Then,software program processes are introduced and the processes contain DSP programs and MCU programs.DSP programs include DSP main program,A/D converting program,PI operating program,external characteristic controlling program,pulse output controlling program and interrupt program.MCU programs include MCU main program,encoder phase discriminating program,data preservation program and communication protocols.All these programs are programmed by C language and the programming method.At last,programs are compiled and debugged and each circuit system is tested.The tests include signals output testing,driving PWM testing,the correctness of protecting circuit.After each part have been tested correctly,test prototype,including no-load voltage testing,sampling circuit testing,pulse output testing,PI parameters tuning,external characteristic testing and pulse phase testing.After testing,analyze the testing data compared to designing data.All tests certificate that the Integrated Pulsed Tandem MIG Arc-Welding Power Source can be able to realize multi-function digital control.Its controlling system is stable and output precision is high.