Vector Magnetic Properties Research Articles

Improvement of E&S modeling for eddy-current magnetic field analysis

This paper presents improvements of Enokizono and Soda (E&S) modeling of vector magnetic properties in arbitrary direction considering alternating and rotating hysteresis of grain-oriented silicon steel sheets. Reluctivities of this modeling were calculated from measurement data obtained through two-dimensional magnetic measurement. However, the measurement was done by only 50 Hz, and the influence of the frequency was not examined fully. In this paper, we examine the frequency dependence of hysteresis curve and present an improved modeling considering frequency dependence of the eddy current.

Two-dimensional (vector) magnetic property and improved magnetic field analysis for electrical machines

In conventional magnetic measurements, magnetic properties are measured under excitation in a single direction, and consequently the results represent the magnetic properties in the measured direction only. These characteristics cannot be applied to analysis, which considers not only an alternating field but also a rotating magnetic field such as transformer and rotating machines. In order to analyze such field’s problems of these electrical machines, we proposed the magnetic properties as vector values using a two-dimensional magnetic measurement method. This paper presents a new magnetic permeability tensor expression by the two-dimensional magnetic properties and its modeling for improved magnetic field analysis.

Improvement of T-joint part constructions in three-phase transformer cores by using direct loss analysis with E&S model

This paper presents the effects of the joint method in the T-joint of three-phase transformer cores on iron losses. The effects of joints on the decrease of core loss have been analyzed by using FEM with E&S model, considering the hysteresis of vector magnetic properties. As a result, we can improve the T-joint part constructions to reduce iron losses in the three-phase transformer cores.

Vector magnetic properties in arbitrary direction of various kinds of magnetic materials

Two-dimensional (vector) magnetic properties under alternating magnetic flux in arbitrary crystallographic direction have been obtained in four typical kinds of magnetic materials. B—H characteristics in arbitrary direction are well derived numerically from two B—H loops of easy axis and hard axis.

Core loss analysis of transformer by improved FEM

We define a new modeling of vector magnetic properties considering hysteresis. Our new expression is introduced into a finite element formulation, and applied to transformer core model. Moreover, we can calculate iron loss in the transformer core. As a result, it is shown that our expression is generally applicable to anisotropic problems considering the hysteresis phenomena.

Study on torque improvement of single-phase induction motor by using FEM

This paper presents the torque properties of an induction motor analyzed by the finite element method considering vector magnetic properties. In order to analyze the machines under rotating magnetic fields, we have to use the two dimensional magnetic properties measured as the reluctivity tensor. In this paper, we propose an induction motor model core that has inclined stator slots and show the basic torque characteristics.

Distribution of local magnetic properties in three-phase induction motor model core

Efficiency improvement of electrical machines, is a very important problem. However the local magnetic properties in core materials have not yet understood fully. On the other hand, the concept of the two-dimensional magnetic property has been reported. It means the relationship between the magnetic field strength vector H and the flux density vector B. They are not usually parallel but have a phase angle in space. This paper presents the measured local vector-magnetic properties in a three-phase induction motor model core.

Direct magnetic loss analysis by FEM considering vector magnetic properties

This paper deals with analysis by FEM for iron losses considering vector magnetic properties. We define the tensor magnetic reluctivity and calculate it from the data measured with two-dimensional measurement method. This numerical method is applied to the direct magnetic loss analysis. As a result, it is shown that the calculated results using our method are in a good agreement with measured ones.

Finite element analysis of transformer model core with measured reluctivity tensor

This paper presents a new expression of the vector magnetic properties under alternating and rotating flux conditions. The expression is defined by an improved reluctivity tensor based on measured results. Moreover, the expression is more accurate than conventional expressions about the approximation of magnetic properties in arbitrary direction. Accordingly, our new expression is introduced into a finite element formulation, and applied to a simple anisotropic magnetic field problem. As a result, it is shown that our expression is applicable generally to anisotropic problems.