Research On Digital Twin-wire Welding Power Supply

Twin-wire welding becomes a hot spot in research of converter power recently. It is a welding technique with high energy efficiency, high quality and with low economic cost which can raise working production efficiency and welding quality. Supported by the foundations of NSFC (NO.50875088) and GDSTC (NO.2008B010400006), a digital twin-wire welding converter power supply, based on DSP, was developed and then, circuit test and process experiments were conducted.A general design of digital twin-wire welding power supply was selected firstly, and two side-by-side IGBT full bridge converter main circuit structures were designed. A hardware control system based on DSP TMS320F2808 was designed, including DSP base circuit, signal feedback circuit, drive circuit, wire driving circuit and protection circuit. The hardware system designed could operate stably after total test through test bench. Constant voltage characteristic was also designed according to the character of CO₂ twin-wire welding process, and software PI control arithmetic was confirmed.A human-machine interactive system was designed based on ARM MCU and CPLD, in which MCU was used for sampling, key pressing and data transmission, CPLD was used for managing LEDs and nixie tube. Thus, digital input and display of parameters in twin-wire welding was achieved.An experiment platform was established for digital twin-wire welding power supply, on which, the digital twin-wire welding power supply was fully tested through a large number of welding experiment, with the help of self-developed 4-channel welding dynamic arc wavelet analyzer. Welding effect of different welding parameters was analyzed through two group of current and voltage wave form collected via welding. Rules were found connected with welding speed and current difference between two wires. That the digital twin-wire welding power supply could achieve twin-wire CO₂ welding effectively was proved by experiment results, and the welding performance well.