Analysis Of Input And Output Signal In Short Circuit Transition Of Arc Welding

CO₂ gas shielded welding began in the early 1950s,since its appearance,it has rapidly developed because of high production efficiency,low cost of welding,good welding quality,excellent welding adaptability and so on,meanwhile,it is widely used in low carbon steel and low alloy steel and other ferrous metal welding materials.However,in the actual welding process,CO2 gas shielded welding usually gets the welded joints of poor mechanical properties due to the unstable welding process.Therefore,it is very important to extend the evaluation method of welding stability and avoid the application of poor welding joints in production.In recent years,researchers have proposed some effective methods for evaluating the stability of short-circuit transitions based on the electrical signals at the output of the welder.However,they are mostly limited to the output of the welder and are rarely involved in the input of electrical signals to the welder.Input as a source of welding process energy,input signal characteristics and welding process changes must have a certain relationship.By studying the relationship between the input signal and the output signal,it can not only deepen the understanding of the electric signal law of the welding process,but also broaden the means of welding process evaluation.Therefore,the analysis of the welding machine input and output signal relationship has great theoretical significance and application value.Based on the above analysis,this paper carried out the following research:1)Build experimental platform.Design the sampling circuit and data acquisition system of the collected electric signal is designed.2)Three sets of welding tests were carried out.Respectively are three kinds of different protective gas under different wire feeding speed short-circuit transition gas-shielded welding test.Using the designed sampling system to collect the input and output electrical signals in the welding process,and pre-processing the collected data to obtain the real welding process data.3)The input power and the input power peak value arithmetic of welder are written and the input power peak value diagram is drawn by MATLAB.The input power peak value and output current signal are processed and analyzed from time domain and frequency domain under different shielding gas feeding speed.And the corresponding relationship between the input and output signal characteristics of the welding process is obtained.4)Using MATLAB/Simulink to module simulate the main circuit model of inverter welding machine with IGBT and IF transformer as the core,and debug the main parameters of the circuit.Simulink is used to module simulate the nonlinear arc load model,and debug the model parameters.The simulation results show that the input and output signals can be simulated effectively,and the input and output terminals of the simulated electric signal are compared and analyzed.