Fuzzy control method of TIG welding source ring closure

Abstract

The invention relates to a closed-loop fuzzy control method for a TIG welding power supply, which comprises the steps: 1) arc current is converted into a corresponding voltage signal through the detection of a current sampling unit, the voltage signal is subject to wave filtration and amplitude limiting and then enters an A / D conversion channel of a DSP to be converted into a digital discrete value If, and a CPU compares the If with a preset welding current variable Ig to obtain a deviation e and the deviation variation rate ec; and 2) the DSP operates a fuzzy control algorithm program according to the e and the ec to solve a control signal u needed by eliminating the e, and transfers the control signal u to a PWM module to directly control the PWM; and two paths of pulse signals which are not overlapped with each other are output through a frequency dividing circuit, are power amplified by a driving chip special for an IGBT, and then drive two groups of IGBT switch tubes respectively to ensure that the switch tubes are conducted at intervals to change the duty factor of output voltage, thereby realizing the control to the current, wherein the fuzzy control algorithm program comprises the fuzziness of the input amount, the operation of fuzzy relation, fuzzy decision, and the accuracy of decision results. The method can better control the constant current value of TIG welding, and has quick response.

Description

Technical field [0001] The invention relates to the technical field of a welding power source control method, in particular to the technical field of a TIG welding power source control method, and specifically refers to a closed-loop fuzzy control method of a TIG welding power source. Background technique [0002] Tungsten Inert Gas Welding (TIG welding) is an ideal method for welding non-ferrous metals and their alloys, such as aluminum, magnesium and their alloys, stainless steel, etc. It has the advantages of stable arc and beautiful weld formation. However, in the welding process on site, due to different working conditions, the arc is interfered by various factors, such as: changes in arc length, unevenness of workpieces, purity of shielding gas, flow rate and fluctuations in power supply grid, etc., will cause welding current The voltage deviates from the stable operating point. If the welding current and voltage can quickly and automatically return to a stable operating po...

AI Technical Summary

Problems solved by technology

However, in the field welding process, due to different working conditions, the arc is disturbed by various factors, such as: changes in the length of the arc, unevenness of the workpiece, purity of the shielding gas, flow rate and fluctuations in the power grid, etc., will make the welding current The voltage deviates from the stable operating point

Images