An Improved Vector Hysteresis Model Incorporating the Effect of DC-Biased Field and its Application to FEM Analysis of Three-Limb Transformer Core

This paper proposes an improved vector hysteresis model for integrating the impact of simultaneous rotating and DC-biased fields on vector magnetic flux density and vector magnetic field strength. Different from the previous vector hysteresis model, the magnetic field strengths of the classical eddy current field and the anomalous field are introduced into the enhanced model. vrk, vhk and v0k are derived to describe two-dimensional magnetic properties under DC-biased magnetization. A precise numerical analysis method for calculating magnetic quantities distribution of transformer core under AC and DC-biased excitation is developed by applying the proposed model into finite element method. Two experimental three-limb transformer core models are set up for the verification of the simulation results. It is shown that, the local magnetic flux density loci acquired experimentally have close agreement with the ones obtained by the proposed model, which proves that the proposed model and the related simulation algorithm are sufficiently accurate.