| Digital inverter welding machine is an important equipment to improve the quality and efficiency of arc welding.Welding machines have been developed in my country for many years,but they are all low-end inverter welding machines.The real high-end welding process still uses foreign welding equipment.Digital welding machines are still in the development stage.The welding machine power supply system is a highvoltage,high-current,strong-interference device,and the different process output requirements corresponding to the power supply make the power supply system more complicated.For this reason,on the basis of the existing welding machine,this paper conducts a detailed study on the shortcomings and application pain points of the existing welding machine,conducts in-depth research on the key issues and difficulties of the digitalization of the electric welding machine,and puts forward unique insights and feasible solutions.In this paper,through the research on the welding process,aiming at the requirements and influence of the welding process on the welding power supply,a welding power supply system that meets the requirements of the welding process is constructed,including welding control system,sampling method,feedback method,PID algorithm,filtering link,main circuit topology,etc.,also put forward the framework and calibration concept of software development,make the software function modular and platform,implement the design concept of "one machine with multiple functions",apply the touch screen to develop a menu-style human-computer interaction system,make welding parameter setting,status parameter monitoring,Expert system operation,communication setting,fault diagnosis,etc.are more convenient and humanized.In terms of the main circuit,the traditional full-bridge inverter power supply topology is modified to avoid the shortcomings of the main transformer bias of the fullbridge topology,and then the soft-switching technology is applied to the full-bridge topology to reduce switching losses.The topology of the digital inverter welding machine for power feeding".In the control system,a double-loop control system based on inner-loop current closed-loop control and outer-loop voltage closed-loop control is adopted to output precisely controlled current and voltage to the digital inverter welding power supply to meet the needs of various processes.The principle and implementation method of outputting DC pulse,AC rectangular pulse,AC triangular waveform and AC sine waveform current are elaborated in detail.Based on the principle of arc length adjustment,the connection between welding wire melting speed and wire feeding speed is established.Through PID adjustment,Output the PWM signal of the electronic power switch to realize the closed-loop control of the entire control system.The strong interference environment of the electric welding machine will cause strong interference to the collected and output signals.At the same time,the electric welding machine is a high-speed control real-time system,and the requirements for the signal are very strict,otherwise the output cannot meet the requirements of the process.For this reason,a large number of noise reduction methods and filtering methods have been researched on electric welding machines,including hardware filtering and software digital filtering.Kalman filtering is undoubtedly very useful for signal processing of high-speed real-time systems.In the PID system,the control range of the electric welding machine is relatively wide,and a set of well-tuned PID parameters often cannot meet the needs of multiple processes,especially in the "one machine with multiple uses" system.Different PID parameters are required to adapt the system.For this reason,the idea of segmented PID is proposed,but the setting of PID parameters is also very complicated.With the help of previous research experience,using adaptive neural network PID,the parameters of PID can be set in the system by itself,satisfying multiple requirements PID needs.In this paper,the main circuit of the inverter power supply is designed in detail and the components are selected,and the functionalized module design of the control circuit is carried out.Combined with various communication interfaces RS232/485,CAN,WIFI,USB,etc.,the industrial site can be realized Master-slave control,LAN control,remote control,remote control using WIFI network,can realize communication with the robot,can use U disk to upload and download the welding parameters of the inverter power supply,etc.This article uses DSP as the main control system and MCU as the humancomputer interaction system.The DSP chip TMS320F28034 has a main frequency of60 M,which fully meets the needs of the digital inverter welding power supply,and is responsible for the control of the entire power supply system and external communication,welding parameters and expert system storage,fault handling and diagnosis.MCU chip 80C196 KC controls the man-machine interface touch screen and LED light display,monitors the welding status,and operates the welding parameters and expert system.The human-computer interaction system can control the DSP,and the host computer can also control the DSP,all of which are set through the human-computer interaction system. |
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