Nonlinear model of a wound iron core traction transformer with the account of magnetic

The paper presents development of an equivalent circuit model of a traction transformer with wound iron core intended for studies of transformer behavior in a traction drive system. The model accounts for the nonlinear BH characteristic and anisotropic properties of the wound core. Derivation of the mathematical model is based on the Lagrange's energy method. Each winding is modeled by a lumped conservative element described by its corresponding nonlinear state function and a lumped linear dissipative element characterized by its resistance. Magnetic hysteresis and eddy current effects are represented by equivalent loop with nonlinear dissipative and magnetic conservative lumped elements. Discrete values of state functions of magnetic conservative elements were obtained by means of Finite Element Method (FEM) computations. Custom build Reduced Scale Traction Transformer (RSTT) was used for experiments and verification of its circuit mathematical model. Results of measurements and simulations were compared in order to verify the model. The comparisons showed good agreement between simulation and experimental results.