Research And Implementation On Double Pulse MIG Welding Machine Control System

Aluminium and aluminium alloy,characterized of fast heat conduction and high heat expansion coefficient,makes the base metal deform easily and can lead to incomplete fusion and lack of penetration,So it's very difficult to weld.However,double pulse MIG welding is quite applicable to the welding of aluminuim alloy due to its intensive heat character.double pulse MIG welding is one of the best solutions for aluminium alloy welding up to now for it can help to reduce the incidence of stomata,gain ideal welding quality and looks.This paper,on the basis of the research home and abroad,focuses on the research over the control system of double pulse MIG welding machine.Firstly,this paper clarifies the working theory of double pulse MIG welding machine,analyzes and makes a comparison between two most advanced wave control methods at present,ultimately adopts the method of current wave modulation and variable speed wire feed to implement double pulse.According to the design requirements of the system function,the hardware overall design and software overall design of the double pulse MIG welding machine control system are given,and the main control chip selection and development environment of the panel,main control board and wire feeder control board are clarified.Secondly,the hardware circuits of double pulsed MIG welding machine control system are designed in detail,including the main circuit of arc welding power supply,panel circuit,main control board circuit,wire feeder control board circuit and driving board circuit.The main circuit adopts the phase-shifted full-bridge resonant soft-switching topology and the "DSP+hardware-driven" control mode.The operating frequency is 20kHz,and IGBT is adopted as the power switching element.The main control board adopts TMS320F2808 chip as control core,while the panel and the wire feeder control board adopts ATmega128A and ATmega64A MCU respectively.The working principle of each module circuit and the schematic diagram of the circuit design are also given in this paper.Then,the paper expounds the software design idea of the panel,main control board and wire feeder control board,gives the design and program flow chart of unified adjustment algorithm,three closed-loop control algorithm based on I-I mode,arc control algorithm,current PI and welding timing.Finally,the simulation and prototype test of the double pulse MIG welding machine control system are carried out.The results show that the double pulse MIG welding machine control system designed in this paper can realize the stable welding process,and the weld line shape is beautiful.It can meet the requirements of welding and welding process design perfectly.