Study On Waveform Control System Used In CO₂ Welding Course Based On TMS320F2812 DSP

The former results show that it is one of the most effective measures to reduce spatter and improve weld bead for the inverter controlled by double-slope waveform control method. But, it is too difficult to meet the requirement at all welding parameters for welding inverter based on electron inductor. Because of the limitation of processing speed and handling ability, the type of inverter based on micro control unit couldn't make full use of those advantages such as rapid dynamic response and high control precision. So the research presented here is concentrating on digitization welding inverter used for CO2 welding, aiming at improving the performance of welding power source.In this paper, we develop a waveform control system using TMS320F2812 DSP and AT89S8252 and establish a sample inverter on the basis of the DSP technology and the embedded system application. Besides, the power system has the function of carbon dioxide gas shielded welding using double-slope waveform control method. In this system, DSP is responsible for the management and control of power source, and micro control unit is in charge of the control of the man-machine interface system. The communication between them is established by RS-232 bus protocol.The CO2 welding process needs the special external characteristic and dynamic characteristic of power source for there are alternately arcing time and short circuiting time at the period of short-circuiting CO2 welding. After debugging the waveform control system and man-machine interface system, we program constant-current control software and research respectively the current and voltage step response of power source. At last, the carbon dioxide welding method is realized in the welding machine controlled by the waveform control program. The simulated load test is also made here. The experiment proved that the welding inverter can control the waveforms precisely and meet the design requirements.Some advices on future research of the welding power source are given, and they would make a found ground for the subsequent study of digitization CO2 inverter based on waveform control.