The High-frequency Pulse Power Used For A New Arc Length Adjustment Method

With the industrial technology continues progress，the container industry and theautomotive industry are development rapidly, at the same time the competition ismore and more fiercely. More and more manufacturers choose sheet as a productionmaterial, it is not only reduce production costs and improve the competitiveness ofenterprises, but also to reduce the use of materials, energy conservation. For assemblyof the sheet, most are adopting welding methods. Improving the level of sheet metalwelding has a very important significance. Welding sheet is sensitive to heat input dueto the heat capacity of the molten pool is very small. Once the fluctuation of weldingheat input, it will cause a burn-through or penetration. Arc length adjustment is in-evitable in welding process. The conventional method is changing the wire meltingspeed by adjusting the total energy of the arc to achieve the adjustment of the arclength, but at the same the heat input is also changed, which is easy to cause weldingdefects.To this end, the subject proposed a new arc length adjustment method: by ad-justing the proportion of heat used for fusion wire in the total heat to achive the stabil-ity of arc length, it does not change the total heat. Therefore, this topic designs a newdigital pulse welding power source, which is based on dsPIC30F6011, dsPIC30F2020as core control chip. The welding power source contains two BUCK circuits, whichoutput constant current. The welding power source can output high frequency pulsecurrent through the current superposition which output by the two BUCK circuits. Wecan change welding wire melting rate to achive arc length adjustment by changingeffective value of current but not changing average value.This article through overall framework design, analysis power main circuit andselect the device used in the circuit. It designs the hardware and software of the weld-ing power control circuit, which implement digital power. It contains design of basevalue output current circuit, design of amplitude value output circuit, the design of thedrive circuit, the design of feedback circuit, design of digital PI control, design of wirefeed speed control system.