| High Efficiency Welding(HEW) features a significant effect on the improvement of productivity, making it a popular study topic in the welding industry. To realize HEW, the further increase of welding current is imperative. As for twin-wire pulsed Gas Metal Arc Welding(GMAW), the interference between the two arcs degenerates as the welding current rises, so it becomes the main hindrance of the raise of rated power of twin-wire pulsed GMAW. Funded by the Natural Science Foundation of China(No.51205136), a study is been conducted on the twin-arc interference of high-power twin-wire pulsed GMAW and its double pulse optimization strategy.Based on the analysis on the principle and characteristic of the twin-wire pulsed GMAW, overall technical scheme of the power supply system for high-power twin-wire pulsed GMAW has been concluded. Topologies of the main circuit of the inverter power supply have been overviewed, and parallel full-bridge topology is adopted based on the requirement of the high-power welding system. Mechanism of the production of the twin-arc interference is analyzed, and the pulsed welding method and double pulse optimization strategy aiming at the interference aforementioned have been worked out.After analyzing the demand for control scheme put forward by the technological requirement of twin-wire pulsed GMAW, overall control scheme of the high-power power supply system for twin-wire pulsed GMAW has been worked out, with hardware control circuits designed, like the voltage and current signal sampling circuit, the fault protection circuit, as well as the IGBT driver circuit; and several programs written like the compensating program based on anti-windup PI algorithm, the single and double pulse synergic program of the three output mode: synchronization, anti-phase, and random, as well as the arc striking and arc suppressing program; in this way multi-phase digital synergic control of the twin-wire pulsed GMAW system is realized. EMC optimization is taken care of when designing the hardware and software of the multi-phase digital synergic control system due to the harsh electromagnetic radiation of the working condition for welding systems.Simulated load test and twin-wire pulsed GMAW technological experiment are conducted with the designed power supply system for high-power twin-wire pulsed GMAW. Experimental result indicates that the designed control system for the power supply fulfills the design requirement, the single and double pulse welding of synchronized, anti-phase and random phase is well realized with high efficiency, and optimized double pulsed welding improves the weld seam quality. High-speed photography experiment of twin-arc for high-power twin-wire GMAW is conducted, and based on the photos of twin-arc shape, twin-arc interference in two welding technology condition of single pulse welding technology and double pulse welding technology is analyzed. Experimental result indicates that twin-arc interference of twin-wire pulsed GMAW can be decreased by adopting anti-phase welding technology; the distribution of arc force is improved by adopting double pulse welding technology, making twin-arc interference be decreased further. |
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