Design Of The Control System For Inverter CO₂ Welding Based On DSP

Nowdays CO₂ welding machine control system is formed by non- numeralization. Accuracy and flexibility and interference of the control system is limited. In this paper, the control system based on DSP of inverter welding is designed. The acquisition of the welding current and voltage signals, A/D transfer, PWM pulse and the control signals is completed by the DSP. The figures used for both physical forms, thus realizing the digital control system.The main body of this paper has been designed signal treatment circuit based on DSP, the signal treatment circuit divides the voltage signal and electric current signal treatment circuit, and has adopt high-accuracy Hall voltage sensor and Hall electric current sensor to be a core component respectively in the circuit, the signal of voltage, electric current is changed suitable voltage signal, to satisfy demand of DSP signal collect. And the signal treatment circuit have the function to put main circuit and control circuit under isolated at the same time. Secondly this paper have designed drive circuit ,this drive circuit adopt drive chip M57959L as special use,this changes 0 -3.3 V PWM pulse that DSP provides into-10V -15 V drive wave form , driving power switch component IGBT.And drive circuit have the function of short circuit/overpower protection at the same time. In order to offer favorable man-machine conversation interface , this paper designed vision circuit constituted by LED, which can displays welding current and voltage in real time according to information provided by DSP. In addition, to ensure normal operation of welding machine and avoid breakdown because of accidents, the paper also designed protecting circuits built up by over-heat, over-current, over-voltage and under-voltage protecting circuits. For workflow of CO₂ welding machine and based on these hardware circuits, this paper adopt modularization programming method , have designed that DSP-based A/D transfer,vision drive, PWM pulse waveform subprograms. After finshing designing hardware and software, a set of control system of CO₂ inverter was construsted, and the experiment verifies that the system is stabile and reliable, demand of designing is achieved .