Multiwinding transformers: a successive refinement method to characterize a general equivalent circuit

A lumped component equivalent circuit has been developed by our team to model the linear electrical behavior of any two winding transformer. Its topology is independent of size and technology and a general method of characterization, exclusively based on external impedance measurements, has been presented. Unfortunately, when some key frequencies are out of the range of the measuring apparatus, several capacitances remain unevaluated. Owing to a new understanding of magnetic and electrostatic coupling, a new successive step approach is presented. At each step, a more accurate circuit, proven to be effective in electronic simulation, is fully characterized. This method suits any number of windings and experimental data will be presented for two and three winding transformers.