Dynamic Power Factor Measurement in A.C. Resistance Spot Welding with Embedded ANN

Today the real-time measurement of the dynamic power factor in resistance spot welding is of increasing importance. On the basis of the welding transformer circuit model, a new measuring method is proposed. This method measures the peak angle of the welding current, and then calculates the dynamic power factor in each half-wave. An artificial neural network is trained off-line and used for online computation of the model parameter. The tailored sensing and computing system ensures that the method possesses a real-time computational capacity and satisfying accuracy. A DSP-based resistance spot welding monitoring system is developed to perform ANN computation. Experimental results suggest that this measuring method is feasible.