Development Of Gas Protection Welding Machine Based On DsPIC30F4011

Gas shielded welding has been widely used in industrial manufacturing due to its advantages of high efficiency and energy saving,low welding cost,all position welding and easy to realize welding automation.However,its disadvantages such as large welding spatter and poor weld forming have not been well solved.This paper studies a gas shielded welding machine based on dsPIC30F4011,which has the advantages of small welding spatter,low welding cost,stable working performance and precise timing control.It has great scientific research value and industrial application value.The main circuit design includes three-phase input rectifier filter circuit,full bridge inverter circuit,main transformer design and output rectifier circuit.Through detailed analysis and calculation,the rectifier bridge module,input filter capacitor,power switch and output rectifier diode are reasonably selected.In view of the disadvantages of IGBT,such as large loss of hard switch and serious electromagnetic interference,the full bridge inverter circuit adopts soft switch design,which makes the super forearm realize ZVS with constant frequency and pulse width modulation,and the lagging arm realize ZCS with constant frequency and constant width,which improves the overall performance of the welding machine.The design of the main transformer is the key and difficult point.From the three aspects of the selection of the magnetic core material,the selection of the magnetic core shape and the design of the coil winding,the comprehensive analysis and design are carried out.The model of the transformer magnetic core is determined to be the nano crystal magnetic core onl-1308040,and the number of turns,strands and strand diameter of the coil are calculated.DsPIC30F4011 is selected as the main control chip in the control circuit to monitor the working state and precise timing control of the welding machine in real time.DSC minimum system,waveform control system and digital wire feeding system are designed.In addition,the sampling circuit and power supply circuit are designed.In order to make the wire feeder work stably and reliably,the digital wire feeding system is designed.The hardware circuit design includes air valve driving circuit,wire feeder speed feedback circuit,SCR rectifier output circuit,welding gun switch and spot With the help of software program,the feeding speed can be stable and the timing can be controlled accurately.With UC3846 as the control core,the pulse width modulation circuit designs a good peripheral control circuit and an indispensable fault protection circuit to achieve the peak current control mode.According to the designed DSC hardware circuit,the corresponding software program is designed.The software program adopts modular design,including program-controlled software design and digital wire feeding software design.Because the inverter welding machine is easy to be affected by the interference signal in the high frequency state,which will affect the normal operation of DSC control system,this paper adopts different hardware and software anti-interference measures,which greatly improves the anti-interference ability of the welding machine.The working frequency of the final designed prototype is 20 k Hz,the rated output power is 19 kw,and its waveform is tested and analyzed.