The Research Of DSP Control System Of CO₂ Welding Inverter Power Source

The digital control system of the welding inverter based on DSP is designed in this paper. In this system, the type of DSP is TMS320LF2407, produced by TI Company .It has high speed (40Hz) and precision (16bits), and provides the ability to realize the digital control system. In the control software design, the process of welding is divided into arc period and short circuit period, and the digital PID control algorithm is adopted. Through the experiment, the waveform of voltage and current by A/D are collected. PWM and D/A are output. And the control system meets the requirement of the arc welding inverter.A prefect control system is big and complex. In this paper, some primary parts of the digital control system are designed, including the hardware system and software system. The closed-loop control system for voltage and current is designed. The feedback signal is sampled, then the analog signal is converted to digital signal, and DSP process the data, then the PWM waveform is output to control IGBT. The digital signal is converted to analog signal to control welding feeding wire system. In the software program, the digital PID algorithm is adopted. The simulation model is established about PID algorithm, credible and applied parameters are provided. A power load experiment of static characteristic and dynamic characteristic is tested on the welding inverter (25kHz).