High Throughput Methods for Functional Magnetic Materials Design
by Heike C Herper of Division of Materials Theory Department of Physics and Astronomy, Uppsala University

To fight global warming and to increase independence from external fuel supplies green energy applications have moved in the research focus. Magnetic materials play a key role in many of these applications, such as electric transportation, wind power generation, or the more recently discussed magnetocaloric refrigeration. The increasing interest in environmentally friendly technologies has triggered the search for new magnetic materials being ecologically and economically superior to the currently existing rare-earth magnetic materials. Computational design has been proven to be a powerful tool for this purpose. In the studies presented here, we combine big data searches and high throughput calculations to identify new candidates for permanent magnets and magnetocaloric applications. The focus is on materials which do not contain heavy rare-earth or expensive 5d elements. Starting from a pool of about existing 1000 phases we apply a combination of filters to extract possible candidates for new permanent magnets or magnetic refrigeration. Phases which pass all filter criteria are investigated in detail using a combination of first principles electronic structure methods and thermodynamic modelling [1,2]. Regarding new permanent magnets a promising example has been found and successfully synthesised showing the characteristics of a good permanent magnet [3]. Funded by the Swedish Strategic Research Foundation (SSF), (Grant EM16-0039), STandUPP, eSSENCE, ERC (synergy grant FASTCORR, project 854843), Knut and Alice Wallenberg foundation (KAW), Swedish National Infrastructure for Computing (SNIC) at PDC and LIU. [1] R.M. Vieira, O Eriksson, A Bergman, H.C. Herper, Journal of Alloys and Compounds 857, 157811 (2021) [2] A. Vishina, O.Y. Vekilova, T. Björkman, A. Bergman, H.C. Herper, O. Eriksson, Physical Review B 101, 094407 (2020) [3] A. Vishina , D. Hedlund, V. Shtender,… H.C. Herper, Acta Materialia 212, 116913 (2021)

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Materials Informatics for the Design of Rare-Earth Reduced Permanent Magnets
by Thomas Schrefl of Christian Doppler Laboratory, University for Continuing Education Krems

High-performance magnets are essential for green technologies. However, these magnets contain a high fraction of critical elements. The transition to carbon free society may lead to a shortage of light and heavy rare-earth elements. In Europe, the additional Dy and Nd consumption in renewables and e-mobility alone in 2050 is 12 and 4 times higher, respectively, than current consumption in all applications [1]. To mitigate supply risks, heavy-rare-earth-free and Nd-substituted magnets are being developed. Materials informatics, combining available data from experiments and computer simulations, opens new possibilities for permanent magnet design and critical element reduction. Permanent magnets can be optimized by considering chemical composition, microstructure, material cost and magnetic performance simultaneously. Machine learning is a tool for the inverse design of permanent magnets. The desired target properties are the starting point for material optimization. For example, we want to make a magnet with a specific coercive field at the magnet's operating temperature and a predefined mixture of chemical elements. Using the power of machine learning-based materials design, we quickly obtain answer to design questions based on all available information ranging from experimental databases to data from ab-initio and micromagnetic simulations. An interactive dashboard for magnet design provides chemical compositions and granular structure of candidate materials that match the desired properties. The financial support by the Austrian Federal Ministry for Digital and Economic Affairs, the National Foundation for Research, Technology and Development and the Christian Doppler Research Association gratefully acknowledged. Ab initio data are provided by the National Institute of Advanced Industrial Science and Technology and the Institute for Solid State Physics, the University of Tokyo under “Program for Promoting Researches on the Supercomputer Fugaku”. [1] European Commission, Critical materials for strategic technologies and sectors in the EU - a foresight study, 2020, doi: 10.2873/58081

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Evaluating the impact of magnetic material selection through multi-disciplinary design optimization
by Ruud Sprangers of Punch Power Train

The vision of Punch Powertrain is to provide powertrains that drive a sustainable world. This vision includes a strong focus on electrification and electric drives combined with an optimal use of magnetic material. To design our next-generation of innovative and affordable electric powertrains, the availability of a multi-disciplinary design optimization platform is of key importance. With this platform, Punch Powertrain is able to make trade-offs between a multitude of design criteria, including performance, cost, efficiency, thermals, structural integrity and NVH. For a given set of design requirements and constraints, Pareto-fronts can be generated and explored to find the most suitable solution(s). This approach has enabled Punch Powertrain to fully optimize the usage of magnetic material via in-depth characterization and comparison of Pareto-fronts generated for various magnetic materials to study their impact on the optimal design of an electric machine. During the presentation, the results of such a comparative study will be presented and discussed.

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High-speed motors/generators – Enabling green technologies in aerospace applications, and limitations with associated materials and components
by Dean Evans of NEMA Ltd

Higher power densities are required to enable greener propulsion technologies in aircraft. 1 method to increase power densities in motors and generators is to increase the rotational speed. This works well when connecting motors in-line with turbines, for example, but also has limitations due to specific components and materials. This talk will present a number of different high-speed motors and generators that have been developed for applications in aerospace technologies and discuss limitations, areas for further research and NEMA’s main focus on enabling high speed motor/generator technologies – high speed magnetic bearings.

Post Assembly Magnetising Of Permanent Magnet Assemblies
by Matthew Swallow of Bunting Magnetics Europe

With the aim of simplifying the manufacturing process and improving safety, Bunting’s technical engineering team has developed technology for post-assembly magnetisation. Subsequently, a complex magnet assembly is constructed un-magnetised and then charged. There are many advantages to post-assembly magnetisation; constructing the magnet assembly is easier and the time is taken shorter, there is also a reduced risk of mistakes occurring during assembly (e.g. incorrect polarity orientation).

High-performance magnet materials based on sintered anisotropic rare earth SmCo and CoFe laminated stator sheets. Where is the limit ?
by Michael Weickhmann of Director Subdivision Magnet Assemblies Vacuumschmelze GmbH & Co KG

This presentation will give an overview of the latest development of Sm-Co highest energy density magnet available today and a combination of CoFe laminated stator stacks point welded sheets to build high performant electrical machines for automotive powertrain and aircraft application. This development called HOMAG was publicly funded by BMBF in collaboration with VAC, Daimler, Maccon, Lange, University Aalen, University Darmstadt and Fraunhofer ISC.

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A Novel Modeling Technique via Coupled Magnetic Equivalent Circuit with Vector Hysteresis Characteristics of Laminated Steels
by Doga Ceylan of TU/e EPE

Modeling electromagnetic devices with laminated steels requires a coupling between electromagnetic simulation models and the hysteresis characteristics of laminated steels. In this talk, a novel modeling technique will be discussed to include the dynamic vector hysteresis characteristics of laminated steels in the formulation of magnetic equivalent circuits, where the fixed-point method is employed for the coupling. The results of the proposed modeling method will be compared with the conventional single-valued magnetization curve. Moreover, the experimental verification of the proposed modeling technique will be presented using the transformer core of TEAM problem 32. It will be shown that the proposed modeling technique is able to estimate the flux density distribution, incremental inductance, induced voltage, and iron loss more accurately than the conventional nonlinear electromagnetic models.

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Hard Magnetic Films: From Micro-Magnet Fabrication to High Throughput Material Studies
by Nora Dempsey of Institut Néel, CNRS

High-performance rare earth transition metal (RE-TM) magnets are used in a wide range of applications and are key components for the transition towards green energy (hybrid-electric vehicles, wind mills). Reducing the size of such magnets to the microscale holds enormous potential for the development of micro-systems (µ-motors, µ-generators, µ-actuators, µ-sensors…) with applications in domains as diverse as tele-communications, consumer electronics, energy management and biotechnology. While the demand for RE-TM magnets is projected to grow significantly, raw material supply risks threaten their future production. In this talk I will show how excellent extrinsic magnetic properties, namely coercivity and remanence, can be achieved in rare earth transition metal films. I will go on to describe techniques used to pattern such films at the micro-scale [1], so as to produce micro-magnets with field gradients of the order of a million T/m. I will give examples of the use of such high performance micro-magnets in various prototype applications. I will finish up by presenting the high throughput fabrication and characterization of compositionally graded films [2], which can be used to guide the future development of bulk magnets which are less dependent on critical elements. [1] Frederico O. Keller et al., IEEE Transactions on Magnetics 58 (2022) 2101005 [2] Yuan Hong et al., Journal of Materials Research and Technology 18 (2022) 1245

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Thermal properties of Barium Hexaferrite Ferrofluid in Ethylene Glycol
by Daniel Zabek of Cardiff University

Recently discovered barium hexaferrite nano-platelets form a ferromagnetic-ferrofluid which exhibits novel magnetic properties [1]. Manufacturing the barium hexaferrite platelets via hydrothermal synthesis remains of fundamental interest and allows for optimisation of structural, magnetic, and morphological properties, which all impact on ferrofluid properties. The advantage of the proposed ethylene glycol-based ferrofluid is low volatility, low toxicity, and high thermal stability. Thermal properties are experimentally determined for the Barium Hexaferrite Ferrofluid in Ethylene Glycol opening the way into a vast number of thermal, electrical, medical, and analytical applications

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Characterization and loss prediction of grain‐oriented electrical steel
by Bram Daniels of TU/e EPE

Electrical steel is a ferromagnetic material specifically designed to possess highly beneficial magnetic properties and a low loss characteristic. For grain-oriented electrical steel this is particularly the case in the so-called rolling direction of the material, a consequence of a number of improvements in the production and composition of the steel. An application for grain-oriented electrical steel is the core of a large power transformer, for which it is critical to model the magnetic loss and hysteresis behavior to get an estimate of the performance and efficiency. This talk will focus on modeling the magnetic iron loss by the well-known loss separation theory of Bertotti, based on measurement data obtained via an Epstein frame, specifically for grain-oriented electrical steel.

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High Temperature Superconductors and their potential in linear motor applications
by Arvind Desikan of TU/e EPE

Over the past 50 years, electric linear motors have firmly established themselves as robust solutions for faster, precise, efficient and high-density actuation in the transportation and automation industry. In every subsequent generation of these motors, improving force density is crucial. This demand is improved by enhancing magnetic and electrical loading. Therefore, significant attention has been given to permanent magnet linear motors to meet the former feature. On the other hand, gradual improvements in the cooling capability enhance the electrical loading. However, a bottle-neck is being reached as use of conventional sources limit these enhancements. Indeed, a more powerful and efficient electromagnetic source is needed for the future. High-temperature-superconductors (HTS) can potentially achieve this breakthrough. In this talk, recent developments in HTS linear motors and its potential for high-dynamic applications are presented. The later desires a periodic motion profile with substantial acceleration delivered in fractions of seconds. Such a high-dynamic application is considered for which two topologies of the HTS linear motor (HLM) are investigated - a set of three-phase AC commutated HTS coils in the stator with permanent magnets in the mover; a set of DC-operated HTS coils in the stator with three-phase AC commutated copper coils in the mover. The improvements and subsequent challenges with adopting such linear motors are presented.

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Dual electromagnetic formulations in magnetoquasistatics
by Léo A.J. Friedrich of ASML

In this talk, the dual nature of Maxwell's equations in terms of fields, potentials, and material properties, is summarized through the structure of the Maxwell's house diagram. Weak formulations are compared between scalar and vector magnetic potentials, for three different benchmarks, in the isogeometric analysis framework, with both linear and nonlinear materials characteristics. Finally, for the four electromagnetic potentials, some examples of post-processing applications are given towards electromechanical design aspects that are beyond the usual solution of electromagnetic fields

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Challenges in the magnetic field and eddy current modelling in high-speed electric machines
by Marko Merdzan of TU/e EPE

As high-speed electric machines are inherently supplied by switched power converters, high-frequency harmonics are inevitably present in the stator current waveform. These harmonics cause significant torque ripple, and induce eddy currents in the rotor, increasing the rotor temperature and potentially causing machine failure in the case of permanent magnet-based high-speed machines. Accurate modeling of the magnetic field and eddy currents caused by distorted stator current waveforms can be extremely time-consuming if the numerical modeling methods are used, as the frequencies of PWM harmonics are much higher than the fundamental frequency. In this talk, the effective mesh-free harmonic method for modeling PWM-supplied high-speed machines is presented as an alternative to the conventional finite element method. This very fast method is extended to utilize PWM voltage input, in contrast to conventional harmonic methods which are typically limited to the current input. The talk will present the results obtained by this method, and discuss modeling aspects specific to high-speed electric machines.

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Medium Frequency Transformers for High Power Applications
by Siamak Pourkeivannour and Mitrofan Curti of TU/e EPE

The solid-state technology is being adopted in the medium to high voltage and power applications as a response to rapidly changing power system trends, such as load profiles, energy flows, types of loads and sources connected to these systems, to name only a few. The passive components, like transformers, are the first that are left exposed to significantly different and harsher operating conditions. The fast-switching patterns of the semiconductor devices are straining the windings and insulation systems to a degree where the material, topologies and models used for the design routines must be reconsidered. In this talk, divided in two parts, a brief introduction on the state-of-art the Medium Frequency Transformers (MFTs) and the motivation for the MFT designs will be given. Next, the challenges and requirements for high-performance of high-power and medium voltage applications will be addressed. The new topology of MFTs with foil windings will be detailed.

Measurement and characterization of ferromagnetic materials for accurate magnetic loss modelling in electrical machines
by Reza Zeinali of TU/e EPE

The problem of magnetic loss prediction in electrical machines has been researched for decades, resulting in various magnetic loss models. These models are identified using the experimental data obtained from magnetic measurement setups. In this presentation, the most common magnetic measurement setups are reviewed, and their operating principle and associated measurement challenges are detailed. These experimental setups are utilized to characterize three magnetic loss models. The accuracy of these models is validated by comparing their results with experimental data obtained from a three-limbed transformer core.

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High accurate magnetic field realization with a passive magnetic circuit towards series production
by Bob van Ninhuijs of VDL ETG Technology & Development

VDL ETG T&D aims to enable the latest technology and make it suitable for series production in the high-tech industry as a tier-one design and contract manufacturer. A particular necessity in this industry is to achieve highly accurate magnetic circuits consisting of soft and hard magnetic material. In the search for the edge of magnetic performance prediction applied in a series production, VDL ETG T&D explores commercial FEM packages, material properties and their variation. In this investigation, a simple magnetic circuit is used to quantify the impact of these aspects on the magnetic field. In addition, the main source of variation considering a series production is identified.

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High power density traction machine modelling for magnetic material selection
by Sigrid Jacobs and Jan Rens of ArcelorMittal

The electrification of transport powertrains is not only steered by sustainability targets, but also by efficient management of critical raw materials. The presentation uses the examples of classic Internal Permanent Magnet machines (IPM), Permanent Magnet Assisted Synchronous reluctance machines (PMaSynRM) and Axial flux machines (AFM); the latter because of its high torque density. For these machines the type of permanent magnets is discussed in a bill of material approach. A parametric study is included regarding the soft ferromagnetic materials’ impact of permeability, saturation, resistivity, on the optimisation potential of the studied machines. Suitable modelling techniques are adopted for the relevant frequency domain.

Optimization of Magnetic Systems through Finite-Element Modelling
by Martijn Leskens of Goudsmit

Finite-element modelling (FEM) is a well-established computational means for system analysis and optimization that can substantially reduce product development time and costs. With this modelling tool the domain of interest is split up in small elements over each of which the fundamental physics equations are solved. For a company that sells (electro-)magnetic systems such as Goudsmit Magnetics it is an important product development and optimization tool because of the ability of relatively accurately predicting the performance of its magnetic systems. In this presentation, it is discussed how FEM is currently applied at Goudsmit. This particularly is done through various applications that are encountered at Goudsmit and where FEM has been involved in analysis and optimization. The presentation provides an idea of both how FEM can be used for the analysis and optimization of (electro-)magnetic systems and of the diversity of industrial applications where (electro-)magnetics is involved. For some applications it is not sufficient to only model the electro-magnetic phenomena but other physical phenomena as well, in particular the product flow in case of separation applications.

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Magnetic measurements of materials at CERN: why, what, and how.
by of CERN

Materials have to display properties compatible with the target application, and assessing how a material behaves under the effect of a magnetic field is crucial for a vast spectrum of applications at CERN. One of our team mandates is performing magnetic measurements of materials in the framework of different CERN projects, experiments, and collaboration agreements with external partners and institutes. This presentation showcases the measurement principles and the test benches we use to verify ever more stringent requirements. Complementary solutions are adopted, some based on industry standards, others internally developed, to perform measurements in a wide range of test conditions, depending on expected material behavior, applied field, and temperature. Experimental results are also presented to provide a deeper insight into our solutions.

Permanent Magnet Segmentation – Improvements of effectiveness, manufacturability and cost
by Mike Königs, Jürgen Prossel of Bomatec AG / Flensburg University of Applied Sciences, Bomatec AG

Permanent magnet segmentation is the State-Of-The-Art technique to reduce eddy current losses in permanent magnets of PMSM. Latest calculation methods in research still neglect major impact factors on segmentation effectiveness. A brief overview over influence factors on PM segmentation effectiveness will be given. Furthermore, latest developments in segmentation technology will be presente

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Accuracy and Limitations of high-precision 3D magnetic field mapper
by Manuel García Pérez of VDL ETG Technology & Development

Highly-accurate magnetic measurements are paramount nowadays in a wide variety of applications within technology development and manufacturing. For our projects we need to characterize and assess the quality of permanent magnets and the performance of specific assembled magnetic circuits. To this purpose, we use a high-end Senis 3D magnetic field mapper. This work depicts the capabilities of this setup, along with the limitations that we have encountered with its usage; focusing on the sources of potential measuring errors and trying to quantify them and correct them where possible

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The way forward of sintered NdFeB for high temperature applications.
by Dr Alexander Furgeri of JL MAG Rare-Earth Europe B.V.

Sintered NdFeB magnets gain their coercivity and the resulting temperature stability from use of heavy rare earth elements, like Dysprosium, Terbium or Holmium. The increasing demand of high temperature stable magnets, driven by electrification of automobiles, results in a price increase of these elements. The whole magnet industry searches for processes of reduction of these elements with keeping or even improving the temperature stability. The last quantum step in this direction was the introduction of grain boundary diffusion. Up to know, customers request homogeneous magnet properties, whereas the potential of diffusion enables further significant raw material savings. This presentation shows further possibilities of raw material savings by using three dimensional inhomogeneous diffusion and how to adapt it for applications.

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Measurement technologies for comprehensive characterisation of soft magnetic materials used in automotive applications
by Dr. Lukasz Mierczak of Brockhaus