Research

13 pages, 4027 KiB

Open AccessArticle

Investigation of the Temperature Field Distribution in an EI Type Iron-Cored Coil Using 3D FEM Modeling at Different Load Conditions

by Denitsa Darzhanova and Ilona Iatcheva

Energies 2023, 16(12), 4581; https://0-doi-org.brum.beds.ac.uk/10.3390/en16124581 - 08 Jun 2023

Viewed by 667

Abstract

In this present paper, results for the temperature distribution in electromagnetic construction in the form of coil coupled with EI-type ferromagnetic core are presented. This construction is typical for small electric transformers (AC operation mode) or chokes—DC or AC operation mode. Investigation has [...] Read more.

In this present paper, results for the temperature distribution in electromagnetic construction in the form of coil coupled with EI-type ferromagnetic core are presented. This construction is typical for small electric transformers (AC operation mode) or chokes—DC or AC operation mode. Investigation has been provided using 3D finite element method computer modeling at various load conditions to simulate power dissipation both in the coil and the core volumes. The results obtained were used to calculate overall thermal resistances toward ambient free air and the thermal resistance between the coil and the core. These results show the important role the thermal resistance between the coil and the core may play for both steady-state and transient device operation. Full article

(This article belongs to the Special Issue Advances in Design of Electrical Machines and Simulation of Electromagnetic Fields)

► Show Figures

Figure 1

16 pages, 5572 KiB

Open AccessArticle

Design Aspects of Conical Coaxial Magnetic Gears

by Valentin Mateev, Miglenna Todorova and Iliana Marinova

Energies 2023, 16(10), 4191; https://0-doi-org.brum.beds.ac.uk/10.3390/en16104191 - 19 May 2023

Cited by 1 | Viewed by 950

Abstract

In this paper, a new design of a conical coaxial magnetic gear was proposed. Conical magnetic gears are considered a logical link between the radial- and axial-field coaxial designs. The modeling of magnetic torques based on the 3D finite element method was developed. [...] Read more.

In this paper, a new design of a conical coaxial magnetic gear was proposed. Conical magnetic gears are considered a logical link between the radial- and axial-field coaxial designs. The modeling of magnetic torques based on the 3D finite element method was developed. The design parameter variations of the conical coaxial magnetic gear were determined and discussed. The magnetic torque density was calculated and compared with that of a cylindrical coaxial magnetic gear with the same size and materials used. An optimal cone angle based on the air-gap length was proposed. Multistage conical coaxial magnetic gears were proposed as a sequence of coupled rotors with increased torque density and reduced magnetic reluctance. The proposed conical coaxial magnetic gears are more compact in size and suitable for integration with electrical machines and variable transmissions. Full article

(This article belongs to the Special Issue Advances in Design of Electrical Machines and Simulation of Electromagnetic Fields)

► Show Figures

Figure 1

24 pages, 13636 KiB

Open AccessArticle

Applied Complex Diagnostics and Monitoring of Special Power Transformers

by Georgi Ivanov, Anelia Spasova, Valentin Mateev and Iliana Marinova

Energies 2023, 16(5), 2142; https://0-doi-org.brum.beds.ac.uk/10.3390/en16052142 - 22 Feb 2023

Cited by 4 | Viewed by 2109

Abstract

As a major component in electric power systems, power transformers are one of the most expensive and important pieces of electrical equipment. The trouble-free operation of power transformers is an important criterion for safety and stability in a power system. Technical diagnostics of [...] Read more.

As a major component in electric power systems, power transformers are one of the most expensive and important pieces of electrical equipment. The trouble-free operation of power transformers is an important criterion for safety and stability in a power system. Technical diagnostics of electrical equipment are a mandatory part of preventing accidents and ensuring the continuity of the power supply. In this study, a complex diagnostic methodology was proposed and applied for special power transformers’ risk estimation. Twenty special power transformers were scored with the proposed risk estimation methodology. For each transformer, dissolved gas analysis (DGA) tests, transformer oil quality analysis, visual inspections of all current equipment on-site and historical data for the operation of each electrical research were conducted. All data were collected and analyzed under historical records of malfunctioning events. Statistical data for expected fault risk, based on long-term records, with such types of transformers were used to make more precise estimations of the current state of each machine and expected operational resource. The calculated degree of insulation polymerization was made via an ANN-assisted predictive method. Assessment of the collected data was applied to allow detailed information of the state of the power transformer to be rated. A method for risk assessment and reliability estimation was proposed and applied, based on the health index (HI) for each transformer. Full article

(This article belongs to the Special Issue Advances in Design of Electrical Machines and Simulation of Electromagnetic Fields)

► Show Figures

Figure 1

17 pages, 7596 KiB

Open AccessArticle

Non-Destructive Electromagnetic Evaluation of Material Degradation Due to Steel Cutting in a Fully Stacked Electrical Machine

by Ahmed Selema, Mohamed N. Ibrahim and Peter Sergeant

Energies 2022, 15(21), 7862; https://0-doi-org.brum.beds.ac.uk/10.3390/en15217862 - 23 Oct 2022

Cited by 6 | Viewed by 1689

Abstract

Although it is well known that the magnetic properties of electrical steel can be deeply affected by the cutting process, it is still not clear how to accurately evaluate these effects on a prototyped machine on its final shape, especially at a high [...] Read more.

Although it is well known that the magnetic properties of electrical steel can be deeply affected by the cutting process, it is still not clear how to accurately evaluate these effects on a prototyped machine on its final shape, especially at a high frequency or a high power rating. This research provides a more practical method for accurate measurement of magnetic losses in electrical steel with consideration of material degradation effects due to the cutting process. Unlike other similar studies, these investigations are conducted not only on a few laminations but also on a complete electrical machine core. For a fair comparison between both cases, backlack bonding is used for lamination stacking since it is the most non-damaging joining technique. Two different test setups are used to measure the steel performance at a wide range of frequency and input power. Furthermore, a full axial length stator of a switched reluctance machine (SRM) is used as a case study to identify the magnetic properties of NO20 electrical steel. Additionally, by comparing the results obtained from the individual laminations and the assembled stator, the extra losses due to the cutting process and material degradation are extracted accurately. Full article

(This article belongs to the Special Issue Advances in Design of Electrical Machines and Simulation of Electromagnetic Fields)

► Show Figures

Figure 1

17 pages, 6119 KiB

Open AccessArticle

Axial Flux Permanent Magnet Synchronous Generators for Pico Hydropower Application: A Parametrical Study

by Vincenzo Di Dio, Giovanni Cipriani and Donatella Manno

Energies 2022, 15(19), 6893; https://0-doi-org.brum.beds.ac.uk/10.3390/en15196893 - 21 Sep 2022

Cited by 2 | Viewed by 1827

Abstract

A pico hydropower plant is an energy harvesting system that allows energy production using the power of the water flowing in small watercourses, and in water distribution network. Axial Flow Flux Permanent Magnet Synchronous Generator (AFPMSG) are particularly suitable for this application, being [...] Read more.

A pico hydropower plant is an energy harvesting system that allows energy production using the power of the water flowing in small watercourses, and in water distribution network. Axial Flow Flux Permanent Magnet Synchronous Generator (AFPMSG) are particularly suitable for this application, being efficient machines that achieve high power with small dimensions. This paper presents a parametrical study of several configurations and topologies of three-phase and single-phase AFPMSG, for pico hydropower application, to assess the most suitable dimensional characteristics for the most energy production using a safe voltage of 25 V. The AFPMSGs here considered has a simple single stator and rotor configuration, commercial-type permanent magnets, and concentric windings, to facilitate their cost-effective construction and the spread of their use also in developing countries. For each AFPMSG considered, the power output was calculated using 3-D modelling and Finite Element Analysis; besides, the different parameters and features that affect the power output were evaluated at different rotational speeds. The results achieving a power density up to 100 W/cm³, at 1000 rpm with energy produced to 1.7 kWh/day. Full article

(This article belongs to the Special Issue Advances in Design of Electrical Machines and Simulation of Electromagnetic Fields)

► Show Figures

Figure 1

21 pages, 7062 KiB

Open AccessArticle

A Nonstandard Path Integral Model for Curved Surface Analysis

by Tadao Ohtani, Yasushi Kanai and Nikolaos V. Kantartzis

Energies 2022, 15(12), 4322; https://0-doi-org.brum.beds.ac.uk/10.3390/en15124322 - 13 Jun 2022

Cited by 1 | Viewed by 1136

Abstract

The nonstandard finite-difference time-domain (NS-FDTD) method is implemented in the differential form on orthogonal grids, hence the benefit of opting for very fine resolutions in order to accurately treat curved surfaces in real-world applications, which indisputably increases the overall computational burden. In particular, [...] Read more.

The nonstandard finite-difference time-domain (NS-FDTD) method is implemented in the differential form on orthogonal grids, hence the benefit of opting for very fine resolutions in order to accurately treat curved surfaces in real-world applications, which indisputably increases the overall computational burden. In particular, these issues can hinder the electromagnetic design of structures with electrically-large size, such as aircrafts. To alleviate this shortcoming, a nonstandard path integral (PI) model for the NS-FDTD method is proposed in this paper, based on the fact that the PI form of Maxwell’s equations is fairly more suitable to treat objects with smooth surfaces than the differential form. The proposed concept uses a pair of basic and complementary path integrals for H-node calculations. Moreover, to attain the desired accuracy level, compared to the NS-FDTD method on square grids, the two path integrals are combined via a set of optimization parameters, determined from the dispersion equation of the PI formula. Through the latter, numerical simulations verify that the new PI model has almost the same modeling precision as the NS-FDTD technique. The featured methodology is applied to several realistic curved structures, which promptly substantiates that the combined use of the featured PI scheme greatly improves the NS-FDTD competences in the case of arbitrarily-shaped objects, modeled by means of coarse orthogonal grids. Full article

(This article belongs to the Special Issue Advances in Design of Electrical Machines and Simulation of Electromagnetic Fields)

► Show Figures

Figure 1

17 pages, 3431 KiB

Open AccessArticle

Analytical Minimization of Interior Permanent Magnet Machine Torque Pulsations by Design of Sculpted Rotor

by Steven Hayslett, Thang Pham and Elias Strangas

Energies 2022, 15(11), 4124; https://0-doi-org.brum.beds.ac.uk/10.3390/en15114124 - 03 Jun 2022

Cited by 1 | Viewed by 1336

Abstract

A new and efficient analytical optimization methodology for the design of rotor features is developed and used in interior permanent magnet motors (IPM). The analytical methodology is based on an extended winding function theory to include the IPM rotor’s primary and secondary reluctance [...] Read more.

A new and efficient analytical optimization methodology for the design of rotor features is developed and used in interior permanent magnet motors (IPM). The analytical methodology is based on an extended winding function theory to include the IPM rotor’s primary and secondary reluctance paths and the non-homogeneous airgap of the rotor sculpt features. The shape and placement of the rotor features, derived from the analytical-based optimization process, show the improvement in torque average and torque ripple of the IPM machine at a fraction of computational effort. The analytical optimization results are validated with finite element analysis via an exhaustive search. Full article

(This article belongs to the Special Issue Advances in Design of Electrical Machines and Simulation of Electromagnetic Fields)

► Show Figures

Figure 1

15 pages, 7088 KiB

Open AccessArticle

Synthesis of Application-Optimized Air Gap Field Distributions in Synchronous Machines

by Ryszard Palka

Energies 2022, 15(7), 2322; https://0-doi-org.brum.beds.ac.uk/10.3390/en15072322 - 23 Mar 2022

Cited by 1 | Viewed by 1032

Abstract

This paper deals with the method of shaping the magnetic field distribution in the air gap of a synchronous machine. The main goal is to obtain a specific distribution of the magnetic field in the machine’s air gap to enable easier powering, to [...] Read more.

This paper deals with the method of shaping the magnetic field distribution in the air gap of a synchronous machine. The main goal is to obtain a specific distribution of the magnetic field in the machine’s air gap to enable easier powering, to increase the torque and power density, or to limit the content of higher harmonics in the induced voltage and torque. This method can be applied for both the electrically excited machines and permanent magnets excited machines. The problem has been reduced to solving a modified system of algebraic equations obtained by the finite element method. The presented examples show the effectiveness of the proposed method both in shaping the contours of the air gap and the magnetization of permanent magnets placed on the rotor. The method can particularly be used in the design of the high-speed synchronous machines. Full article

(This article belongs to the Special Issue Advances in Design of Electrical Machines and Simulation of Electromagnetic Fields)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Advances in Design of Electrical Machines and Simulation of Electromagnetic Fields

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (8 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI