AC spot-welding dynamic electric resistance real-time measuring device and method

Abstract

A kind of AC spot welding dynamic resistance real time measure instrument and method in the welding technology field, the said instrument includes: the welding transformer, a couple of inverse parallel silicon control, Holtz current sensor, minitype Lowe's loop, net pressure synchronization loop, current zero cross pulse detection loop, the silicon control starting circuit, welding current signal conditioning circuit, current differential coefficient signal conditioning circuit, sound-light alarm circuit, clock and replacement circuit, periphery drive circuit, keyboard and display circuit, communication and interlocked interface circuit, DSP control system. The method is that: uses embedded artificial NN calculate the angle of welding dynamic power factor and the current flow, then calculate the silicon control whole flow current virtual value, calculate the dynamic resistance in the spot welding process by using the ratio of the dynamic power factor and the whole flow current virtual value. This invention can detect the angle of welding dynamic power factor in quarter cycle, the instrument is simple, the real-time ability is good, the measurement precision is high.

Description

technical field [0001] The invention relates to a device and method in the field of welding technology, in particular to a device and method for real-time measurement of AC spot welding dynamic resistance. Background technique [0002] During the spot welding process, the current field, temperature field and contact resistance are constantly changing, so the resistance in the welding zone is also changing. The dynamic resistance is the law of resistance change during the heating and cooling process of the solder joint. The dynamic resistance reflects the dual effects of the spot welding current and the voltage between the electrodes, and can better reflect the formation process of the weld nugget, and is more sensitive to the surface state of the weldment, the change of the material thickness, the current shunt and the change of the power supply voltage. Therefore, people use the relationship between the dynamic resistance and the nugget to develop the dynamic resistance met...

AI Technical Summary

Problems solved by technology

Its disadvantage is that the power factor of the welding circuit is submerged within the trigger angle of the thyristor (φ cannot be measured, and the use of the current lag angle ψ instead of the power factor angle will cause a measurement error of about 10%, and the inductive reactance X L It will also change due to the insertion of ferromagnetic objects in the circuit. Different transformers and welding machine arm lengths will affect the inductive reactance X L , so that the dynamic resistance measurement error multinomial accumulation

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