| Twin-wire pulsed MIG welding technology is attracting greater attention and hasbecome the focus of welding researchers home and abroad, for its advantages of highefficiency, quality and easy automation. Nevertheless, domestic research on it commencesrather late and the local production of such kind of twin-wire welding equipment in batchproduction is not achieved. Especially, the study on integrative twin-wire pulsed MIGwelding equipment is less. Under the funding of National Natural Science Foundation ofChina (No.51205136), in conjunction with technologies on power electronics and digitalcontrol, this paper presents a research on the digital control system based on STM32microcontroller unit for integrative twin-wire pulsed MIG welding power supply is presented, theircharacteristic and application is analyzed.Firstly, the features of twin-wire pulsed MIG welding and the existing implementationsare analyzed. The control system’s overall plan of integrative twin-wire pulsed MIG weldingpower supply is proposed. And the analysis of main-circuit topology of the power supplyinverter is presented. To meet the requirements of control system for twin-wire pulsed MIGwelding power supply, the selection method of external characteristic and the multi-phasedigital control system are put forward.Secondly, the hardware and software of the multi-phase digital control system forintegrative twin-wire pulsed MIG welding based on STM32are designed. Also,anti-disturbance design of the hardware and software is approached via investigatingdisturbance source of welding location. Constant current amplitudes at the peak and at thebase of both the master and slave pulse(I+I) are required in twin-wire pulsed MIG welding,leading to the unique external characteristic because of which the anti-integral saturation PIalgorithm is adopted to get access to stable control of the current amplitudeThirdly, a digital system controller with a human machine interface (HMI) based onSTM32, ZLG7290B IC, film switch panels and rotating encoders is designed, so thatparameters of the pulsed MIG welding power supply can be set, stored and displayed accurately. Hardwares about STM32, ZLG7290B and rotatingencoder interfaces’ circuit havebeen designed, so has been the corresponding software. The HMI communicates with thewelding process control system through the RS-232bus, thus the digitalization of HMI isachieved.Finally, the technological test of integrative twin-wire welding was conducted with theequipment of integrative twin-wire pulsed MIG welding power supply and its multi-phasedigital control system. The results of the experiment demonstrate that the developedintegrative twin-wire power supply’s control system meet the design requirements, and thatthe integrative twin-wire welding process was realized in the three types of phase outputmode: synchronization, alternation and random. And the merits of integrative twin-wirepulsed MIG welding are stable welding process, high speed, and high quality welding seam，should the welding parameters be appropriate. |
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