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.