The Design Of The Full‐bridge Digital Inverter Weldingsource

At present, the inverter welding source has been widely used at home and abroadbecause it has the energy conservation, material saving, good control performance, quickdynamic response, easy real-time control and so on. The development of modern powerelectronics and high-power inverter technology continues to mature, which promote therenovation of the inversion welding source. The welding source not only has the generalelectric source characteristics, but also meets the electrical characteristics of the arc loadrequirement. Based on the development tendency and the electrical characteristics ofwelding source, a full-bridge digital inverter welding source was researched and designed.Firstly, the structure of main circuit with inverter welding source was designed in thispaper. The main circuit includes rectifier, inverter, high-frequency transformer and the laterrectifier. The inverting circuit is the full-bridge topology, the inverting frequency was20KHz and the switching power units are IGBT, including the design of IGBT parametercalculation, selection and absorption protection circuit.Secondly, the control circuit of inverter welding source was designed in detail. Thecontrol circuit includes minimum system of single chip, parameters preset and displaycircuit, PWM circuit, data acquisition circuit, drive circuit, protect circuit. Acquired currentsignal were inverse feed backed with PWM, then, output of the chip UC3846werecontrolled through PI regulator. As a result, the external characteristic was controlled.Then, the design of software and the program structure for control system wereanalyzed. The software for control system was designed according to the timingrequirements. The program of display penal, parameters display and adjustment and theinterrupt service were highlighted. Some of the key programs were also showed.Finally, the offline and online debugging were done for this welding source, and thekey waveform traces were given and analyzed, The experiment showed that the weldingsource can realize parameter and technological requirement request After thedebugging, specimens were welded to test this power source, it is proved that this source issuitable.