Research On Multi-waveform GMAW Welder Controlled By "DSP+MCU" Dual-core

With the development of waveform control technology,there are many waveforms used in actual welding occasions,among which pulse and double pulse waveforms are the most common.As the digital technology of welding machines matures,generalized double pulse waveforms also appear.Therefore,based on the research of domestic and foreign welding machines,this subject uses the "DSP+MCU" dual core as the control core to design a "multi-wave" GMAW welding machine that uses a constant-speed wire feeding method to adjust the duty cycle to stabilize the arc length.The meter's "multiwaveform" GMAW welding machine can output a variety of waveforms on one welding machine,mainly DC,pulse,and double pulse waveforms,so that the welder can adapt to the welding of multiple materials.This article first determined the main circuit structure,and calculates some Components parameter and main circuit simulations completely.The main circuit mainly includes input rectifier filter circuit,soft switch full-bridge inverter circuit,stepdown circuit,output rectifier filter circuit and so on.Secondly,this paper designs the corresponding software and hardware for the "DSP+ MCU" control system.The hardware circuit mainly includes DSP minimum system and expansion circuit,signal acquisition and conditioning circuit,PWM signal generation circuit,IGBT drive circuit design,MCU minimum system,man-machine interface design,air supply and welding wire feeding circuit and so on.The DSP chip chooses TI's product TMS320F2812,which has rich on-chip resources and a main frequency of up to 150 MHz,which can meet the requirements of basic welding machines.However,For the stable operation of the welding power source and improve the performance of the welding power source,the single-chip STC89C58RD+ and TMS320F2812 are selected to form a dual-core control system.DSP is mainly responsible for the program control and algorithm realization of the welding machine,and Single-chip microcomputer is responsible for human-machine interface interaction data,etc.Thirdly,according to the digital closed-loop control system designed by the control system,only the current loop is used to derive the transfer function of the designed GMAW welding power source.At the same time,in the light of the characteristics of pulse welding,different PI algorithms are used for different stages of the pulse,and the characteristics of pulse waveforms under single PI control and double PI control are compared.Thirdly,according to the digital closed-loop control system designed by the control system,only the current loop is used to derive the transfer function of the designed GMAW welding power source.It is extremely valuable to analyze and improve the control system based on the obtained transfer function,and then optimize the welding machine.Finally,the designed pulse GMAW welding machine was debugged.The welding machine debugging process includes the control system test,no-load voltage test,external characteristics test of welding power source,welding process test and other processes.The process test mainly carried out the surface surfacing test of carbon steel,stainless steel and aluminum alloy,and used the welding parameter acquisition system to collect the welding current and voltage waveform.From the welding test process and welding current and voltage waveform,the current and arc length are stable,and the splash is bitterly small,the welding process is stable.The waveform output such as pulse is realized,and the welding machine meets the design goal.