External Characteristic Control Of SMAW Inverter Power Based On DSP

The external characteristic shape of arc welding inverter not only influce the stability of "Power-Arc" system,but also be related to the steady of welding parameter,and only when we choose the proper external characteristic curve for a certain form of arc static character,that can ensure both the stable condition of system and the steady of welding parameter.This paper discusses three classic external characteristic control modes of arcwelding inverter------analogous control.MCU control,DSP control,and we can drivea conclusion that the DSP control mode is the key element to realize the digitalization of arc welding inverter.The hardware circuit of arc welding inverter control system has been designed,including the feedback and sample circuit of arc power voltage and current,and DSP minimum system.According to the external character control,we accept PI algorithm as the control strategy,and after establishing the system's controlling model,the simulation of control system has been carried out on Matlab,and the PI's ideal parameters K_p,K_i have been worked out.The system's software includes the A/D conversion program,PID calculation , generating program of PWM signal .At last,we design a experiment flatform,which is based on PC,oscilloscope , waveform generator,SEED-DSK28016.The experiment proves the feasibility of control software system of arc welding inverter.