scholarly journals Electromagnetic Analysis and Comparison of Conventional-Wound Cores and Octagonal-Wound Cores of Distribution Transformers

2010 ◽  
Vol 670 ◽  
pp. 477-486 ◽  
Author(s):  
I. Hernández ◽  
J.M. Cañedo ◽  
J.C. Olivares-Galván ◽  
Pavlos S. Georgilakis
Keyword(s):  
Eddy Current ◽  
Electromagnetic Analysis ◽  
Excitation Current ◽  
3D Fem ◽  
Electrical Steels ◽  
Eddy Current Losses ◽  
Distribution Transformers ◽  
Core Losses ◽  
Comparative Results ◽  
2D And 3D

This paper presents comparative results of an electromagnetic study performed in two different wound core transformer configurations in order to know the best configuration that reduce excitation current and core losses. The results show that octagonal wound-core (OWC) reduces the excitation current and eddy-current losses with respect conventional-wound core (CWC). The results were obtained applying 2D and 3D FEM simulations, taking into account the non-linear properties of the core. In the last part of this paper, several grades of grain oriented electrical steels and the combination of them are analyzed to find the best mixing percentage to reduce eddy-current losses and excitation current.

Determination of eddy current losses and hysteresis losses in magnetic circuits of electrical machines

2020 ◽  
pp. 54-58
Author(s):  
S. M. Plotnikov
Keyword(s):  
Eddy Current ◽  
Magnetization Reversal ◽  
Eddy Currents ◽  
Technical Problem ◽  
Electrical Machines ◽  
Eddy Current Losses ◽  
Hysteresis Losses ◽  
Magnetic Circuits ◽  
Core Losses ◽  
Reversal Frequency

The division of the total core losses in the electrical steel of the magnetic circuit into two components – losses dueto hysteresis and eddy currents – is a serious technical problem, the solution of which will effectively design and construct electrical machines with magnetic circuits having low magnetic losses. In this regard, an important parameter is the exponent α, with which the frequency of magnetization reversal is included in the total losses in steel. Theoretically, this indicator can take values from 1 to 2. Most authors take α equal to 1.3, which corresponds to the special case when the eddy current losses are three times higher than the hysteresis losses. In fact, for modern electrical steels, the opposite is true. To refine the index α, an attempt was made to separate the total core losses on the basis that the hysteresis component is proportional to the first degree of the magnetization reversal frequency, and the eddy current component is proportional to the second degree. In the article, the calculation formulas of these components are obtained, containing the values of the total losses measured in idling experiments at two different frequencies, and the ratio of these frequencies. It is shown that the rational frequency ratio is within 1.2. Presented the graphs and expressions to determine the exponent α depending on the measured no-load losses and the frequency of magnetization reversal.

scholarly journals Prediction of Eddy Current Losses in Cooling Tubes of Direct Cooled Windings in Electric Machines

Mathematics ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 1096 ◽  
Author(s):  
Mohamed Nabil Fathy Ibrahim ◽  
Peter Sergeant
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Eddy Current ◽  
Electric Machines ◽  
Iron Core ◽  
Commercial Software ◽  
Eddy Current Losses ◽  
Switched Reluctance ◽  
Element Simulation ◽  
Core Losses

The direct coil cooling method is one of the existing cooling techniques for electric machines with concentrated windings, in which cooling tubes of conductive material are inserted between the windings. In such cases, eddy current losses are induced in those cooling tubes because of the time variant magnetic field. To compute the cooling tubes losses, either a transient finite element simulation (mostly based on commercial software), or a full analytical method, which is more complex to be constructed, is required. Instead, this paper proposes a simple and an accurate combined semi-analytical-finite element method to calculate the losses of electric machines having cooling tubes. The 2D magnetostatic solution of the magnetic field is obtained e.g., using the free package “FEMM”. Then, the eddy current losses in the tubes are computed using simple analytical equations. In addition, the iron core losses could be obtained. In order to validate the proposed method, two cases are investigated. In Case 1, a six-toothed stator of a switched reluctance machine (SRM), without rotor, is employed in which six cooling tubes are used while in Case 2 a complete rotating SRM is studied. The proposed method is validated by a 2D transient simulation in the commercial software “ANSYS Maxwell” and also by experimental measurements. Evidently, the proposed method is simple and fast to be constructed and it is almost free of cost.

Non-linearity of Hysteresis and Eddy Current Losses of Single-phase Distribution Transformers

2021 ◽  
Author(s):  
Filipe Freire Santos ◽  
Gustavo Paiva Lopes ◽  
Estacio Tavares Wanderley Neto ◽  
Jansen Paula Villibor ◽  
Gabriel Henrique Faria ◽  
...  
Keyword(s):  
Eddy Current ◽  
Single Phase ◽  
Phase Distribution ◽  
Eddy Current Losses ◽  
Distribution Transformers

Calculating the main and leakage inductance matrix of the 3-column 15-winding autotransformer

2011 ◽  
Vol 60 (3) ◽  
pp. 215-222
Author(s):  
Damian Mazur ◽  
Marek Gołębiowski
Keyword(s):  
Finite Elements ◽  
Eddy Current ◽  
3D Models ◽  
Finite Elements Method ◽  
Calculation Methods ◽  
Eddy Current Losses ◽  
Voltage Supply ◽  
Leakage Inductance ◽  
2D And 3D

Calculating the main and leakage inductance matrix of the 3-column 15-winding autotransformer The aim of this paper is presentation and comparison of calculation methods of the inductance matrix of a 3-column multi-winding autotransformer. Main and leakage autotransformer inductance was obtained using finite elements method. Static calculations were made at the current supply for 2D and 3D models, and mono-harmonic calculations were made at the voltage supply. In the mono-harmonic calculations the eddy current losses were taken into account, this made it possible to study relationship between the autotransformer parameters and the frequency. Calculations were made using Ansys and the authors' own programs in Matlab.

Evaluation of eddy current losses in the cover plates of distribution transformers

2004 ◽  
Vol 151 (5) ◽  
pp. 313-318 ◽  
Author(s):  
S.V. Kulkarni ◽  
J.C. Olivares ◽  
R. Escarela-Perez ◽  
V.K. Lakhiani ◽  
J. Turowski
Keyword(s):  
Eddy Current ◽  
Eddy Current Losses ◽  
Distribution Transformers ◽  
Cover Plates

A new analytical approach to determine slotting based eddy current losses in permanent magnets of PMSM taking into account axial and circumferential segmentation

2015 ◽  
Vol 34 (2) ◽  
pp. 398-412 ◽  
Author(s):  
Cornelius Bode ◽  
Wolf-Rüdiger Canders ◽  
Markus Henke
Keyword(s):  
Eddy Current ◽  
Analytical Approach ◽  
Permanent Magnets ◽  
Eddy Currents ◽  
3D Fem ◽  
Eddy Current Losses ◽  
Content Type ◽  
High Frequencies ◽  
Reaction Field ◽  
3D Fea

Purpose – The purpose of this paper is to calculate slotting-based eddy currents in permanent magnet excited synchronous machine (PMSM) taking into account axial and circumferential segmentation of magnets. Design/methodology/approach – An analytical approach to calculate eddy current losses in PM caused by slotting harmonics of PMSM is presented. The eddy current reaction field is taken into account as well as axial and circumferential segmentation of the magnets. Findings – The analytical model provides results comparable to 3D-FEM calculations even at high frequencies at reduced computation costs. To generalize the results the magnetic Reynold’s number is introduced. Originality/value – Taking into account the axial and circumferential segmentation in the PDE; the approach is much more accurate compared to known approaches; accuracy is comparable to 3D-FEA.

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