Linear Circuit Model of the Three-phase Insulated Core Transformer Power Supply

Analysis of the terminal characteristics of the three-phase multi-winding insulated core transformer (ICT) requires a precise physical model. A linear equivalent electrical circuit model is proposed and constructed to facilitate the ICT design based on the principle of duality. It is composed by leakage inductances between adjacent windings, leakage inductances introduced mainly by the discrete insulation gaps, as well as ideal transformers. The value of each leakage inductance depends on the geometrical dimensions of the core, gaps or windings and the property of magnetic materials. Both short circuit simulations and self and mutual inductance matrix of transformer windings are employed to determine precisely each inductance. To validate the equivalent circuit, the magnetic flux leakage in a three-stage three-dimensional (3D) ICT is quantitatively analyzed.