A dynamic equivalent network model of the skin effect

An equivalent electrical model of the skin effect in round wires is presented. The model includes a combination of frequency-independent resistors and inductors which is suitable to use in conventional time-domain simulators. Canonical ladder networks have been modified by including self and mutual inductances between tubes. The elements and the circuit topology are defined according to the fields in the wire and they are also based on a decomposition of the wire in successive concentric tubes. Moreover, an extra inductor that captures the external inductance of the winding is also included in the network. The impedance of this network matches the exact analytical impedance of the round wire over a frequency range that depends of the number of elements. The network can be used for transient analysis as well as for providing steady-state response for repetitive input waveforms. The effect of the thicknesses of the tubes and the number of tubes on the accuracy of the model is analyzed. The measured impedance of a flat multi-turn coil wound with a round wire is compared with impedance calculated by using the proposed network and good agreement has been observed.