Themistoklis D. Kefalas and Antonios G. Kladas
This paper aims to present an accurate representation of laminated wound cores with a low computational cost using 2D and 3D finite element (FE) method.
Abstract
Purpose
This paper aims to present an accurate representation of laminated wound cores with a low computational cost using 2D and 3D finite element (FE) method.
Design/methodology/approach
The authors developed an anisotropy model in order to model laminated wound cores. The anisotropy model was integrated to the 2D and 3D FE method. A comparison between 2D and 3D FE techniques was carried out. FE techniques were validated by experimental analysis.
Findings
In the case of no‐load operation of wound core transformers both 2D and 3D FE techniques yield the same results. Computed and experimental local flux density distribution and no‐load loss agree within 2 per cent to 6 per cent.
Originality/value
The originality of the paper consists in the development of an anisotropy model specifically formulated for laminated wound cores, and in the effective representation of electrical steels using a composite single‐valued function. By using the aforementioned techniques, the FE computational cost is minimised and the 3D FE analysis of wound cores is rendered practical.
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Keywords
Athanasios Sarigiannidis, Minos Beniakar and Antonios Kladas
This paper aims to introduce a computationally efficient hybrid analytical–finite element (FE) methodology for loss evaluation in electric vehicle (EV) permanent magnet (PM…
Abstract
Purpose
This paper aims to introduce a computationally efficient hybrid analytical–finite element (FE) methodology for loss evaluation in electric vehicle (EV) permanent magnet (PM) traction motor applications. In this class of problems, eddy current losses in PMs and iron laminations constitute an important part of overall drive losses, representing a key design target.
Design/methodology/approach
Both surface mounted permanent magnet (SMPM) and double-layer interior permanent magnet (IPM) motor topologies are considered. The PM eddy losses are calculated by using analytical solutions and Fourier harmonic decomposition. The boundary conditions are based on slot opening magnetic field strength tangential component in the air gap in the SMPM topology case, whereas the numerically evaluated normal flux density variation on the surface of the outer PM is implemented in the IPM case. Combined analytical–loss evaluation technique has been verified by comparing its results to a transient magnetodynamic two-dimensional FE model ones.
Findings
The proposed loss evaluation technique calculated the total power losses for various operating conditions with low computational cost, illustrating the relative advantages and drawbacks of each motor topology along a typical EV operating cycle. The accuracy of the method was comparable to transient FE loss evaluation models, particularly around nominal speed.
Originality/value
The originality of this paper is based on the development of a fast and accurate PM eddy loss model for both SMPM and IPM motor topologies for traction applications, combining effectively both analytical and FE techniques.
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Keywords
A. Haniotis, A. Kladas and J. Tegopoulos
To identify interactions existing between electromagnetic, electric and mechanical phenomena in variable speed permanent generator wind‐turbines and propose a methodology enabling…
Abstract
Purpose
To identify interactions existing between electromagnetic, electric and mechanical phenomena in variable speed permanent generator wind‐turbines and propose a methodology enabling oscillations analysis.
Design/methodology/approach
Evaluation of the accuracy of alternative approaches such as traditional fundamental and higher harmonic representation as well as coupled field, circuit and mechanical techniques based on the finite element method to represent such phenomena.
Findings
Low frequency oscillations observed experimentally necessitate strong coupling between electromagnetic, electrical and mechanical phenomena.
Research limitations/implications
The techniques adopted are limited to two‐dimensional configurations, while possible three‐dimensional air‐gap eccentricity is not considered.
Practical implications
Special consideration should be paid by the wind turbine controller to attenuate the studied oscillations.
Originality/value
Development of an adequate modelling methodology enabling consideration of low frequency oscillations.