The Research On Main Circuit Of Low Energy Input Welding System Based On DSP

With the global development of the car industry, automobile lightweight hasbecome the development trend.General using of aluminum and aluminum alloys andreducing thickness is one main ways to lightening.So there is application value to carryout research on the high quality welding technology of aluminized steel.This paper present a low energy input welding system that base on push-pullshort-circuit transfer.The system consists of digital welding power source and afeeding mechanism.This paper’s main work is designation of the main circuit andfeeding mechanism. The main circuit uses a soft switch and full-bridge inverterstructure, selectes IGBT as the inverter device, the inverter frequency is20KHz. Torealize real time closed loop control, high performance DSP TMS320F2812is adoptedas control kernel.This paper mainly discuss the principle and designation of rectified filter circuit,inverter circuit, high-frequency transformer, output rectifier and output filter, pulsewidth modulation (PWM) circuit, drive circuit, IGBT protection circuit,and alsointroduced the anti-interference measure of the main circuit and control circuit.The feeding mechanism adopts two wire feeders.The main feeder is DCmotor,which extract welding wire from wire reel. Auxiliary feeder is push-pull motor,itserve to input and retract the wire.When short-circuit signal was dectected,the controlcircuit would feeback the signal to wire feeder.Then wire feeder retract the wire andsnap the drop throught mechanical power. The wire feeder push the wire in the arcingstage still the next short-circuit is deteced. The push-pull wire feeder adopts a ACservo with low moment of inertia and fast responsible and the moving curve of thewelding wire is set by special software.The digital welding power source and the wire feeding mechanism are tested inthis paper.The test results verify that the inverter power source has rapidresponse-speed,high reliability, a strong ability of anti-interface;the forward-reversalrotation of the motor can work at the frequency more than20Hz,which meet thedemand of push-pull short-circuit transfer welding process. Finally, The mainproblems were described when the pulsed MIG welder is debugging in this article,and provided reference to improve unified welding in the future.Main problem and need improvement in the system design is described in detail in this paper andprovided reference to system optimization in the future.