Logo: to the web site of Uppsala University

uu.sePublications from Uppsala University
Change search
Link to record
Permanent link

Direct link
Publications (10 of 72) Show all publications
Eriksson, S. & Silva, M. D. (2023). Comparison of Simulation Methods for Angular Dependency when Modeling Demagnetization. In: 2023 IEEE International Magnetic Conference, INTERMAG: . Paper presented at IEEE International Magnetic Conference (INTERMAG), MAY 15-19, 2023, Sendai, JAPAN. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Comparison of Simulation Methods for Angular Dependency when Modeling Demagnetization
2023 (English)In: 2023 IEEE International Magnetic Conference, INTERMAG, Institute of Electrical and Electronics Engineers (IEEE), 2023Conference paper, Published paper (Refereed)
Abstract [en]

Rare earth element free magnets, such as ferrites, are weaker than their more common alternatives and therefore more prone to demagnetization. Additionally, in permanent magnet electrical machines they are commonly tangentially magnetized and placed in a spoke-type geometry to enhance the magnetic field. In this geometry, the magnets are subject to inclined fields, which are normally not accounted for when evaluating demagnetization risk. In this paper, different methods for demagnetization of permanent magnets are applied to two motors under two distinct loading conditions and the results are compared. It is concluded that it is more important to consider inclined fields when studying ferrite magnets than rare earth element magnets. The common, simplified method of omitting inclined fields is shown to be the most conservative method for evaluating demagnetization. However, more precise results can be reached with methods taking inclined fields into account, especially if the models are adapted for the specific magnet type. Two motors with similar performance have been designed, one with rare earth element magnets and one with ferrites. The motor with ferrites is more sensitive to demagnetization and the bulk of the magnet reaches the demagnetization limit at a lower current than for the motor with rare earth element-based magnets. Finally, demagnetization of magnets is compared for two different rotor positions, emphasizing the importance of considering rotor position when evaluating demagnetization risk.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2023
Series
International Conference on Magnetics, ISSN 2150-4598
Keywords
coercive force, demagnetization, finite element analysis, permanent magnet motors
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-520980 (URN)10.1109/INTERMAG50591.2023.10265101 (DOI)001090594700055 ()979-8-3503-3246-9 (ISBN)
Conference
IEEE International Magnetic Conference (INTERMAG), MAY 15-19, 2023, Sendai, JAPAN
Funder
Swedish Energy AgencyStandUp
Available from: 2024-01-18 Created: 2024-01-18 Last updated: 2024-02-09Bibliographically approved
Simonsson, I., Eriksson, S. & Bernhoff, H. (2023). Design and Simulation study of 40 MW PM Generator for the CRAFT. In: Tande, J. O. G.; Kvamsdal, T.; Muskulus, M. (Ed.), EERA DeepWind conference 2023: . Paper presented at EERA DeepWind Conference / 20th Deep Sea Offshore Wind R and D Conference, January 18-20, 2023, SINTEF, Trondheim, Norway. Institute of Physics Publishing (IOPP), Article ID 012010.
Open this publication in new window or tab >>Design and Simulation study of 40 MW PM Generator for the CRAFT
2023 (English)In: EERA DeepWind conference 2023 / [ed] Tande, J. O. G.; Kvamsdal, T.; Muskulus, M., Institute of Physics Publishing (IOPP), 2023, article id 012010Conference paper, Published paper (Refereed)
Abstract [en]

Design studies of two counter rotating permanent magnet (PM) synchronous generators have been performed. The two 40 MW generators have been designed and compared for the Counter Rotating Axis Floating Turbine (CRAFT) with different air-gap diameters. The generators are modelled with validated full physics finite element method (FEM) which also includes dynamic simulations. The simulations are performed by using an electromagnetic model. The model is described by combined field and circuit equations and is solved in a finite element environment. The stator winding of the generators consists of circular cables and the rotor consists of buried ferrite PM. The generator with smaller air-gap diameter will have lower material costs due to smaller frame but higher due to use of more active materials. A comparison of the counter rotating generators with a traditional direct drive has also been performed by maintaining the same voltage but reducing the rotational speed by half. This shows that a generator with a higher rotational speed will have lower material costs due to smaller dimensions and lower weight. Furthermore, a design variation, to reduce the cogging and harmonic content of the voltage by changing the pole shoe, was analyzed. In conclusions, a 40 MW generator design for the CRAFT has successfully been simulated with a multi-physics-FEM. The advantages of using a counter-rotating generator has been established.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2023
Series
Journal of Physics Conference Series, ISSN 1742-6588, E-ISSN 1742-6596 ; 2626
Keywords
Synchronous generator, Wind power, CRAFT, Ferrite PM, simulations
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-523972 (URN)10.1088/1742-6596/2626/1/012010 (DOI)001147057400010 ()
Conference
EERA DeepWind Conference / 20th Deep Sea Offshore Wind R and D Conference, January 18-20, 2023, SINTEF, Trondheim, Norway
Available from: 2024-02-28 Created: 2024-02-28 Last updated: 2024-02-28Bibliographically approved
Ibrayeva, A. & Eriksson, S. (2023). Dynamic Modeling of a Generator With Anisotropic Nonlinear Permanent Magnets in Finite Element Method Software. IEEE Transactions on Magnetics, 59(9), Article ID 7401308.
Open this publication in new window or tab >>Dynamic Modeling of a Generator With Anisotropic Nonlinear Permanent Magnets in Finite Element Method Software
2023 (English)In: IEEE Transactions on Magnetics, ISSN 0018-9464, E-ISSN 1941-0069, Vol. 59, no 9, article id 7401308Article in journal (Refereed) Published
Abstract [en]

In this article, a method of dynamic modeling of nonlinear permanent magnets (PMs) with recoil lines in 2-D finite element analysis (FEA) software was presented. COMSOL Multiphysics 6.0 FEA software was used in this study. The method is implemented through the variable utilities. The simulation results of a spoke-type synchronous generator for a wind turbine with anisotropic aluminum-nickel-cobalt (Alnico) 5, 8B, and 9 grades were used to exemplify the model and compared. The proposed methodology can be used for the simulation of nonlinear PMs with recoil lines and includes reversible and irreversible losses of magnetization of nonlinear PMs. The effect of the magnetic field from the stator winding on nonlinear PMs during normal operation and short circuits was studied. The modeling results were compared to the model without any demagnetization and a previous study with recoil lines and averaged minimum magnetic flux points. The no-load (NL) voltages were compared before and after a demagnetization. The dynamic model showed considerable demagnetization of Alnico magnets during normal operational and three-phase short circuits. Alnico 5 and 9 showed higher sensitivity to short-circuit currents and the short-circuit currents caused remagnetization of the upper part of the magnet in the opposite direction. The anisotropy of the PM implemented in the model improved the magnetic field simulation inside the magnet and partially protected the magnet from demagnetization by inclined fields. At last, the method was experimentally verified by tests on an iron core.

Place, publisher, year, edition, pages
IEEE, 2023
Keywords
Aluminum-nickel-cobalt (Alnico), COMSOL, demagnetization, finite element method (FEM), nonlinear permanent magnets (PM), PM synchronous generator (PMSG), recoil line
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-514058 (URN)10.1109/TMAG.2023.3296966 (DOI)001061030600003 ()
Funder
Swedish Research Council, 2018-04617
Available from: 2023-10-17 Created: 2023-10-17 Last updated: 2024-04-22Bibliographically approved
Lind, E., Bergman, D. & Eriksson, S. (2023). Effect of Drive Cycle Quantification on Electric Motor Efficiency. In: 12th International Conference on Power Electronics, Machines and Drives (PEMD 2023): . Paper presented at 12th International Conference on Power Electronics, Machines and Drives (PEMD 2023), Brussels, Belgium, October 23-24, 2023 (pp. 96-104). Institution of Engineering and Technology, 12
Open this publication in new window or tab >>Effect of Drive Cycle Quantification on Electric Motor Efficiency
2023 (English)In: 12th International Conference on Power Electronics, Machines and Drives (PEMD 2023), Institution of Engineering and Technology, 2023, Vol. 12, p. 96-104Conference paper, Published paper (Refereed)
Abstract [en]

One way to evaluate real life electric vehicle performance is through drive cycle analysis. However, performing Finite Element Method (FEM) analysis is computationally heavy and optimisation of motor efficiency across all operating points using FEM is time demanding. One way to solve this is by changing the resolution of the drive cycle. The objective of this study is to investigate how different resolutions affect the results, specifically in terms of energy, losses and overall drive cycle efficiency. This study shows, through both analytical calculations and FEM simulations, that it is possible to greatly decrease the number of operating points with only a minimal impact on the overall drive cycle efficiency. There does not seem to exist a universal rule to this which span different drive cycles. However, the quantifications of all drive cycles exhibit a similar pattern, with increased efficiency instability for lower resolutions. For the Worldwide Harmonised Light Vehicles Test Procedure drive cycle, a decrease of 6.4 times in operating points only affects the maximum efficiency deviation by 0.036 percentage points. At this resolution, over half of the energy is distributed along only 25 points, making these a good starting point for electric motor design and optimisation.

Place, publisher, year, edition, pages
Institution of Engineering and Technology, 2023
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-528753 (URN)10.1049/icp.2023.1984 (DOI)978-1-83953-950-3 (ISBN)
Conference
12th International Conference on Power Electronics, Machines and Drives (PEMD 2023), Brussels, Belgium, October 23-24, 2023
Funder
Swedish Energy Agency, P51788-1StandUp
Available from: 2024-05-27 Created: 2024-05-27 Last updated: 2024-06-14Bibliographically approved
Ibrayeva, A., Lind, E., Silva, M. D., Ghorai, S. & Eriksson, S. (2023). Measurement and Modelling of Hysteresis Curves for Nonlinear Permanent Magnets at Different Inclination Angles. In: 2023 IEEE International Magnetic Conference (INTERMAG): . Paper presented at IEEE International Magnetic Conference (INTERMAG), May 15-19, 2023, Sendai, Japan. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Measurement and Modelling of Hysteresis Curves for Nonlinear Permanent Magnets at Different Inclination Angles
Show others...
2023 (English)In: 2023 IEEE International Magnetic Conference (INTERMAG), Institute of Electrical and Electronics Engineers (IEEE), 2023Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents the measurement results of the BH/MH curves of the Alnico 8 (LNGT40) with recoil loops and a mathematical model for the calculation of the average magnetic flux density in a cubic permanent magnet. The measurements were performed with a Vibrating Sample Magnetometer (VSM). The magnet samples have a cubic shape with 3 mm sides. BH curves in preferred (easy) and transverse directions and recoil loops were measured and compared to Alnico 9 (LNGT72) as well as to the data from the supplier. The load line of the cubic magnet in 0 A/m applied magnetic field was found. A mathematical model was developed which can approximate the MH a curve for an applied field with an arbitrarily chosen angle between the field and easy axis, given MH a curves for 0o and 90o. Also, a simplified general model of a cubic permanent magnet in the air and calculation results of stored energy and hysteresis losses were presented.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2023
Series
International Conference on Magnetics, ISSN 2150-4598, E-ISSN 2150-4601
Keywords
Alnico magnets, BH curve, Demagnetization, Permanent Magnet, Recoil Line
National Category
Other Physics Topics Other Electrical Engineering, Electronic Engineering, Information Engineering Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-520985 (URN)10.1109/INTERMAG50591.2023.10265100 (DOI)001090594700054 ()979-8-3503-3246-9 (ISBN)979-8-3503-3247-6 (ISBN)
Conference
IEEE International Magnetic Conference (INTERMAG), May 15-19, 2023, Sendai, Japan
Funder
Swedish Research Council, 2018-04617StandUp
Available from: 2024-01-18 Created: 2024-01-18 Last updated: 2024-04-22Bibliographically approved
Silva, M. D. & Eriksson, S. (2023). Meta-Models for Torque Optimization of Spoke Type Permanent Magnet Synchronous Machines. In: 2023 24th International Conference on the Computation of Electromagnetic Fields (COMPUMAG): . Paper presented at 24th International Conference on the Computation of Electromagnetic Fields (COMPUMAG), May 22-26, 2023, Kyoto, Japan. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Meta-Models for Torque Optimization of Spoke Type Permanent Magnet Synchronous Machines
2023 (English)In: 2023 24th International Conference on the Computation of Electromagnetic Fields (COMPUMAG), Institute of Electrical and Electronics Engineers (IEEE), 2023Conference paper, Published paper (Refereed)
Abstract [en]

The design of internal permanent magnet synchronous machines (IPMSM) is a complex task that often includes multiple objectives and constraints. Lately, a lot of research has been focused on the reduction or elimination of rare-earth elements (REE). To achieve that, the use of ferrite permanent magnets (PM) and the enhancement of reluctance torque are the most common solutions. In this paper, three different meta-models are developed and used in the optimization process to maximize the torque of a Spoke Type PMSM (Spoke) with ferrite PM taking into consideration both reluctance and magnetic torque. These meta-models are based on 1-dimensional convolutional neural networks (1DCNN), gaussian process regression (GPR) and polynomial chaos expansion (PCE). This study shows that the GPR-based meta-models generally present the lowest absolute error. Although, regardless of the different performance, all three meta-models achieve similar optimized solutions.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2023
Keywords
Convolutional Neural Networks, Gaussian Process Regression, Polynomial Chaos Expansion, Genetic Algorithm, Permanent Magnet Machines, Optimization
National Category
Computational Mathematics Control Engineering
Identifiers
urn:nbn:se:uu:diva-524973 (URN)10.1109/COMPUMAG56388.2023.10411775 (DOI)001163580700004 ()979-8-3503-0105-2 (ISBN)979-8-3503-0106-9 (ISBN)
Conference
24th International Conference on the Computation of Electromagnetic Fields (COMPUMAG), May 22-26, 2023, Kyoto, Japan
Funder
StandUp
Available from: 2024-03-15 Created: 2024-03-15 Last updated: 2024-04-25Bibliographically approved
Silva, M. D., Lind, E., Ibrayeva, A., Ghorai, S. & Eriksson, S. (2023). Model for Angular Dependency of the Intrinsic Coercivity of Ferrite Permanent Magnets. In: 2023 IEEE International Magnetic Conference, INTERMAG: . Paper presented at IEEE International Magnetic Conference (INTERMAG), MAY 15-19, 2023, Sendai, JAPAN. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Model for Angular Dependency of the Intrinsic Coercivity of Ferrite Permanent Magnets
Show others...
2023 (English)In: 2023 IEEE International Magnetic Conference, INTERMAG, Institute of Electrical and Electronics Engineers (IEEE), 2023Conference paper, Published paper (Refereed)
Abstract [en]

In internal permanent magnet synchronous machines (IPMSM), the use of ferrite permanent magnets is being studied as an alternative to rare-earth elements-based permanent magnets, such as NdFeB. However, demagnetization measurements of ferrite magnets are rarely published and such information is crucial for an efficient electrical machine design with ferrite magnets. In this paper, we present measurements of partial demagnetization on ferrite permanent magnets subject to inclined external magnetic fields. From the measurements done, mathematical models are developed for Y30 and Y40 samples that defines a relationship between the intrinsic coercivity and the inclination of the external demagnetizing field. Furthermore, from the primary results, the angular dependency of hysteresis losses and relative permeability are also explored, as well as their impact on the design of IPMSM.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2023
Series
International Conference on Magnetics, ISSN 2150-4598
Keywords
Angular Demagnetization, Ferrite Magnets, Intrinsic Coercivity, Magnetic Field Modeling
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-520987 (URN)10.1109/INTERMAG50591.2023.10265092 (DOI)001090594700046 ()979-8-3503-3246-9 (ISBN)
Conference
IEEE International Magnetic Conference (INTERMAG), MAY 15-19, 2023, Sendai, JAPAN
Funder
StandUp
Available from: 2024-01-18 Created: 2024-01-18 Last updated: 2024-02-09Bibliographically approved
D. Silva, M. & Eriksson, S. (2022). On the Mitigation of Leakage Flux in Spoke Type Permanent Magnet Synchronous Machines. In: 2022 International Conference on Electrical Machines (ICEM): . Paper presented at 2022 International Conference on Electrical Machines (ICEM), Valencia, 5-8 September, 2022 (pp. 302-308). IEEE
Open this publication in new window or tab >>On the Mitigation of Leakage Flux in Spoke Type Permanent Magnet Synchronous Machines
2022 (English)In: 2022 International Conference on Electrical Machines (ICEM), IEEE, 2022, p. 302-308Conference paper, Published paper (Refereed)
Abstract [en]

The use of rare-earth elements in permanent magnets rises economic, environmental and supply-chain related concerns. Instead, ferrite magnets have been researched as an alternative. The magnetic flux concentration capacity of the Spoke Type Permanent Magnet Synchronous Motor (PMSM) and the low magnetic remanence of the ferrite magnet make them complementary strategies towards the desirable performance. However, if restricted to conventional manufacturing processes and materials, the mechanical design is a challenging step of the development of these machines. This paper explores how mechanical constraints impact electromagnetic performance. To access the interdependency of the performance and the mechanical constraints, finite element analyses are done both in the mechanical and electromagnetic domain. The results show that the mechanical constraints have an impact on the performance, although it is possible to reduce it by adapting the design to the electromagnetic and mechanical properties of the electrical steel.

Place, publisher, year, edition, pages
IEEE, 2022
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science
Identifiers
urn:nbn:se:uu:diva-492077 (URN)10.1109/icem51905.2022.9910669 (DOI)978-1-6654-1433-3 (ISBN)978-1-6654-1432-6 (ISBN)
Conference
2022 International Conference on Electrical Machines (ICEM), Valencia, 5-8 September, 2022
Funder
Swedish Energy Agency
Available from: 2023-01-02 Created: 2023-01-02 Last updated: 2024-02-09Bibliographically approved
Frost, A. E., Temiz, I., Eriksson, S. & Leijon, M. (2022). Power flow in the air gap of linear electrical machines by utilization of the Poynting vector: Part 1 - Analytical expressions. The Journal of Engineering, 2022(4), 377-388
Open this publication in new window or tab >>Power flow in the air gap of linear electrical machines by utilization of the Poynting vector: Part 1 - Analytical expressions
2022 (English)In: The Journal of Engineering, E-ISSN 2051-3305, Vol. 2022, no 4, p. 377-388Article in journal (Refereed) Published
Abstract [en]

Analytical solutions and estimations for the power flow in the air gap of linear electrical machines of different geometries are derived from Poynting's theorem. The different geometries considered are flat one-sided, multi-sided, and tubular linear electrical machines. The radial power flow for all considered geometries is dependent on the area of the air gap, the electric field, the magnetic field, and the load angle. The tangential power flow for both flat one-sided and tubular linear electrical machines is dependent of the area of the air gap, number of poles, the electric field, the magnetic field, and the load angle. The number of poles could be increased to decrease the tangential power flow in flat linear electrical machines. The expression for the tangential flow in tubular linear electrical machines is so complicated that it is difficult to draw conclusions from it.

Place, publisher, year, edition, pages
Institution of Engineering and Technology (IET), 2022
Keywords
Poynting vector, Linear electrical machine, Wave power, Hybrid vehicles, Stirling micro-generators, Air craft launch systems, Artificial hearts
National Category
Energy Engineering Other Engineering and Technologies
Identifiers
urn:nbn:se:uu:diva-382401 (URN)10.1049/tje2.12121 (DOI)000742742300001 ()
Funder
Swedish Energy Agency
Available from: 2019-04-25 Created: 2019-04-25 Last updated: 2024-04-05Bibliographically approved
Frost, A. E., Sjölund, J., Eriksson, S. & Leijon, M. (2022). Power flow in the air gap of linear electrical machines by utilization of the Poynting vector: Part 2 - Simulations. Paper presented at Institution of Engineering and Technology. The Journal of Engineering, 2022(9), 883-891
Open this publication in new window or tab >>Power flow in the air gap of linear electrical machines by utilization of the Poynting vector: Part 2 - Simulations
2022 (English)In: The Journal of Engineering, E-ISSN 2051-3305, Vol. 2022, no 9, p. 883-891Article in journal (Refereed) Published
Abstract [en]

Different types of linear generators are simulated and their power flow in the air gap is investigated. The results are compared to the analytical expressions derived in Part 1. The simulations and the analytical expressions in Part 1 show the same general behavior, but the magnitudes are lower for the analytical expressions. One explanation for the difference in magnitude can be that the harmonics of the electric and magnetic fields contribute to the power flow, which is not accounted for in the analytical expressions. Due to results from Part 1, it is investigated if changing the number of poles can decrease the tangential power flow while the normal power flow stays the same. As was suspected, changing the number of poles affected several other factors, which lead to an increase in the normal power flow when increasing the number of poles, even though the electrical power was the same. The tangential power flow also decreased for three out of four generators. Thereby, increasing the number of poles with the same length of the machine, at the cost of reduced pole-pitch, should be done with precaution.

Place, publisher, year, edition, pages
Institution of Engineering and Technology, 2022
Keywords
Poynting vector, Linear electrical machines, Simulation, FEM, Wave power, Stirling micro-cogenerator
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Energy Engineering
Identifiers
urn:nbn:se:uu:diva-439749 (URN)10.1049/tje2.12167 (DOI)000827693100001 ()
Conference
Institution of Engineering and Technology
Funder
StandUp
Available from: 2021-04-09 Created: 2021-04-09 Last updated: 2024-05-16Bibliographically approved
Projects
Basic studies of magnetic properties of permanent magnets in electrical machines [2010-03950_VR]; Uppsala UniversityModelling novel nonlinear permanent magnet materials for energy applications [2018-04617_VR]; Uppsala University; Publications
Ibrayeva, A., Lind, E., Silva, M. D., Ghorai, S. & Eriksson, S. (2023). Measurement and Modelling of Hysteresis Curves for Nonlinear Permanent Magnets at Different Inclination Angles. In: 2023 IEEE International Magnetic Conference (INTERMAG): . Paper presented at IEEE International Magnetic Conference (INTERMAG), May 15-19, 2023, Sendai, Japan. Institute of Electrical and Electronics Engineers (IEEE)Westerberg, A., Boggavarapu, S. R. & Eriksson, S.Anisotropic Model of Nonlinear Permanent Magnets in Finite Element Method Software.
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-8598-2565

Search in DiVA

Show all publications