The Design Of Welding Power Source With Inverter Technology And High Working Frequency

The welding power supply with inverter technology and high working frequencyis the most popular technology in the world now. The main benefits is witten down asbelow: Outstanding control ability,Good quality of welding,better dynamicstability,low weight,high effect and PF,easily causing arc,rapider weldingspeed. It is studied as the mainstream and direction technology of the welding powersupply equipment in the world now.This paper employed the FB-PS circuit (full brigde and phase shift modulation).At first, we analyze the zero switching principle of the FB-PS circut. We analysed theenergy exchange process, identified the resonant condition of the lead and lag bridges.We employed the UC3895 to control the main circuit, employ the 4 IGBT to switchat 0 voltages.The switching frequency is as high as 100kHZ. We assembled high speedphotoelectric cells, voltage comparators and MOSFETs into a high speed drivingmodule of the IGBT. It increased the working frequency of the welding power supplyinto 100 KHZ, higher than the frequency of the similar products,then the cubage ofthe transformer of the power supply reduced half, the cubage of the total productreduced much,too.The quality of welding is excellent for the output current is stable. For fixing theoutput current and protecting IGBT and improving the quality of welding, we usedUC3895 limit the output current in every cycle. The timely adjustment reduced thevariety of current and welding splash.We calculated the resonant time of the lead and lag bridge, found the lag bridgelacking the energy to resonat. We added a assistant resonant circuit to complement.The assistant resonant circuit balanced 2 bridges, and the main circuit becamesimplier.For improving the rising speed of the welding arc, we employed a invertingcircuit as the assistant arc causing circuit. It cause arc rapider when the bulk capacitorreleased current. It is useful to some material which is difficult to weld.