A novel methodology for high-frequency lumped equivalent circuit of an isolated transformer winding construction based on frequency response analysis signal morphology interpretation

A novel auto-synthesis method is proposed to construct the mutually coupled equivalent circuit of an isolated air-core transformer winding based on the signal morphology interpretation of its measured frequency response analysis (FRA) only. Therefore, this approach aims to determine the model parameters from the frequency sub-bands (low, medium and high frequency), each of which reflects its dominant parameters, where the parameter identification procedure is done from their corresponding sub-band separately. Besides, the optimisation algorithms have difficulties in estimating the nearly unique lumped circuit parameter in a large search space. For this reason, based on analytical simplifications, two novel dynamic autonomous methods have been proposed to restrict the search space bounds of the inductances and the capacitances. Finally, real case studies were used on actual air-core windings to validate the ability of the proposed method to perform an automated synthesis. Consequently, a nearly unique equivalent circuit model has accomplished automatically with high accuracy.