Research On Control Strategy Of Integrated Double - Arc Pulse MIG Coal Connection

Twin arc pulse MIG welding is a welding method of low energy input.At present, the commonly adopt double power to working.Due to the double power system is complex,coordination control is difficult, volume is too large,and the choice and implementation of MIG welding power source control system is restricted by weld manufacturability.According to the above problem,this paper puts a effective design idea of integrated double arc pulse MIG welding power source to solve the problem of coordinated control,and further study control strategy of integration of the twin arc pulse MIG welding power source.First,the characteristics and the way of implementation of dual power supply control system was analyzed on this paper,and according to the characteristics and control requirements of the twin arc pulse MIG welding,puts the integrated design plan of double arc pulse MIG welding power source.The main arc and the arc circuit were controlled by a DSP control system,problems of structure complicated and coordination control difficult of dual power supply control system were solved.The main arc circuit and arc circuit were constructed based on the three-phase input rectifier filter circuit,IGBT inverting circuit,the output rectifier filter circuit.IGBT inverting circuit is one of the most important step to arc welding power source,so the controlled IGBT limited bipolar full bridge inverting circuit was used.At the same time,parameter was calculated and model was selected to the main components of arc circuit.The simulation model of the integration of system model of double arc pulse MIG welding power source was built based on three-phase input rectifier filter circuit,IGBT inverting circuit,output rectifier filter circuit,and the control system model was built,it has the PWM waveform generator,digital PID controller,the adaptive fuzzy PID controller.It show that the later control effect is better through the simulation results of the digital,the adaptive fuzzy PID controllers.At the same time,the way of current feedback of main arc circuit and arc circuit was used to constanting output current,based on method of voltage feedback of main arc circuit to control the wire feeding speed of wire feeding machine,so as to guarantee the stability of arc length.The welding process of integration of the twin arc pulse MIG of welding power source was simulated by running the Simulink model.According to the design idea of digital integration,the hardware circuit and software programming of integration of the twin arc pulse MIG welding power source were designed.First of all,the smallest integrated digital control system based on DSP F2812 was designed in the aspect of hardware,realized duty ratio,phase matching of current waveform between the main arc circuit and arc circuit.In order to ensure accuracy and stability,safety work of control system,thevoltage and current feedback control circuit,A/D protection and correcting circuit,over-voltage and over-current protection circuit,over-heat protection circuit,driving circuit of IGBT were designed,on this basis,the corresponding software was designed.Based on PWM waveform procedures,AD sampling procedures and fuzzy adaptive PID program,making output of the integration of the twin arc pulse MIG welding power source is more accurate and stable.Finally,the welding test was down,collected data of welding voltage and current in the process,compared with the simulation data,the results found that this design scheme and designed hardware circuit can meet the demand of welding.