Pulsed Mig Welding Digital Control System

PMIG welding (Pulse Metal Inert Gas welding) is a high-quality welding method. It is developed widely for its good direction transition, less splashed material and nice figure. And PMIG welding power supply is developed quickly with the extending of PMIG welding. But, as the development of technology, the shortcomings of traditional analogue control circuit have become the bottleneck for further promotion of the PMIG welding. This paper carried on a thorough research to the PMIG welding. On the base of system simulation and MCU (Micro Controller Unit) +DSP (Digital Signal Processing) technique, full digital control system design of PMIG is presented.The different types of droplet transfer in PMIG welding were investigated. The results show that the type of "one pulse one drop" should be the first choice in PMIG welding because of its stable welding process and sound weld formation. A PI regulator with variable parameters is adopted for flexibly and accurately controlled pulse current-wave form. The experimental results validated pulse current's rising and falling edge can be adjusted respectively and flexibly, the stable state precision of peak and base current is improved.The modeling of PMIG welding system based on Matlab/Simulink is relative ideal, and the simulation result is not consistent well with the experimental one now. This paper presents an integrated simulation model for full digital controlled PMIG welding system with Matlab/Simulink, and it mainly consists of power inverter, digital control system and dynamic arc-load model. A system simulation study was done for full digital PMIG welding, and a method of connecting dynamic arc-load model to the system with controlled current source was adopted, in addition, the simulation results were utilized to study the issues of digital control PMIG welding in this paper.Multi-processor is adopted to design the fully modularization digitized PMIG welding system. The main control system is designed by micro control unit(MCU) and digital signal processor (DSP) to make up of double processor control system. The...