Finite-Element Modeling and Measurements of Flux and Eddy Current Distribution in Toroidal Cores Wound From Electrical Steel

Despite the apparent relative simplicity of the wound toroidal geometry, numerical modeling techniques are very difficult to implement due to the inherent large mesh size required to model a laminated core or spiral geometry. Recent advancements in computing capabilities have made the simulation and the study of such devices more feasible. Finite-element modeling of toroidal cores wound from grain-oriented electrical steel was conducted to accurately represent their magnetic circuits in order to calculate the internal magnetic flux distribution, its interaction with core geometry, and to be able to predict the associated magnetic losses. The general flux distribution trends agree with measured results from identical cores. The interlaminar flux and the associated induced planar eddy currents were also calculated. The measurements were performed using a series of search coils enclosing every five turns. In each case, the core was magnetized at 50 and 400 Hz under controlled sinusoidal flux density up to 1.5 T.