Research On Welding/Plasma Cutting Power Source Control Optimization Based On Arc Characteristics

Arc welding and plasma cutting are common in industrial applications processingmethods, and the welding or cutting qualities are directly influenced by the source property.So reasonable source topology and its control strategy is manual welding and cutting playsan important role on special occasions. In arc welding and plasma cutting power controllerdesign, the arc is usually equivalent to a fixed load. But it is found that the measured arcand plasma arc is a more special kind of load through research which need higherrequirements on the power supply design. Based on the arc characteristics, machine formanual welding and cutting controller has been improved and optimized to improve theirwelding and cutting results.Through the simulation and measurement of the plasma arc it is got that its currentvoltage characteristics. According to the characteristic, the controller is improved bychanging the switching condition for conventional parallel double loop control methodfrom fixed parameters to variable parameters. Through the method the success rate of arcstriking in low current condition is improved, while ensuring stability of the large electricsystem.Welding arc characteristics was measured and analyzed. The arc load is more volatilein the low current. Conventional current PI controller design cannot fit the dynamicperformance of the arc on the power requirements, so the use of sliding mode controlmethod is proposed in this paper to improve the system dynamic performance. First, bymodeling the system under the current sliding mode control, the equivalent sliding controlexpression is obtained, which is equal to the duty cycle of the converter. A method toreduce influence of load changing on equivalent is proposed. In order to eliminate thesteady state error, the double current error integral is added to the controlled volumebesides the original amount include current error, current error differential and integral.Finally, the dynamic performance of the SMC design is tested by simulation andexperiment which can enhance the quality of welding...