19eng06 hefmag

HEFMAG Project Summary

Publishable Summary for 19ENG06 HEFMAG

Metrology of magnetic losses in electrical steel sheets for high-efficiency energy conversion


Overview

Magnetic steel is used for electric motors/generators and transformers, and in both cases the energy losses occurring in the cyclic magnetising of the material are significant. Due to the drive to increase energy efficiency, improved methods are required to assess these energy losses. This project aims to develop and validate methods and experimental setups for traceable magnetic loss measurements in thin magnetic steel sheets extending the induction, frequency and temperature ranges beyond the current IEC 60404 standards; and to study and model power losses under real operating conditions. This will facilitate improved design and performance of magnetic and power electronics devices in support of the Ecodesign Directive 2009/125/EC and the United Nations 2030 Agenda Sustainable Development Goals


Need

The drive to improve energy efficiency, reduce consumption and curb CO2 emissions has led to the introduction of increasingly stringent EU and national legislation related to energy efficiency and emissions reduction. Magnetic steel sheets are the core of electric motors, generators, and transformers, which produce and convert virtually all the energy obtained from conventional and renewable sources. Due to the cyclic magnetising of the steel sheets the energy losses that occur are very significant and can easily reach up to 10 %. The ongoing drive for miniaturisation of devices and high-speed rotating machines require increased working frequencies, and steel producers are therefore striving to develop thinner and highly energy-efficient grain-oriented (GO) and non-oriented (NO) magnetic steels, with enhanced permeability, suitable for kHz frequencies. Novel products based on electrical steel require magnetic loss measurements and modelling under extreme operating conditions, with high temperature, 2D excitation, distorted flux with high harmonic content, skin effects and dc currents.


Objectives

The overall objective of the project is to support the development and characterisation of high efficiency electromagnetic machines (e.g. electric motors and transformers) which operate close to saturation induction and at high temperatures and frequencies, through (i) the development and validation of methods and experimental setups for traceable magnetic loss measurements in thin magnetic steel sheets extending the induction, frequency and temperature ranges beyond the current IEC 60404 standards and (ii) the study and modelling of power losses under real operating conditions, thus facilitating improvements in the design and performance of magnetic and power electronics devices as required by the Ecodesign Directive 2009/125/EC.

The specific objectives of the project are:

  1. To build and validate an improved metrological infrastructure for the determination of power losses with relative standard deviation () down to 1 %, using Single Sheet and Epstein frame magnetic circuits in electrical steel laminations at induction values close to saturation and at frequencies ranging from DC to 10 kHz with flux waveforms of different harmonic content. The dynamic magnetic characterisation will target novel thin laminations with thickness as low as 0.10 mm for non-oriented steels and 0.18 mm for grain-oriented materials.

  2. To build and validate a new metrological infrastructure for Epstein frame measurements up to 155 °C, corresponding to the “F class” insulation (IEC 60085 and IEC 60034-1), to match the typical operating temperatures of electric motors, with a direct impact on loss and efficiency evaluation, since the current standard measurement temperature is 23 °C ± 5 °C.

  3. To study and model power losses in thin sheets within a DC-MHz frequency regime, with the help of fluxmetric, magneto-optical characterisation techniques as well as scanning probe techniques for the sub-µm regime.

  4. To use one-dimensional and two-dimensional measurements and physical models, taking into account the non-uniform flux profiles due to the skin effect, in order to bridge the gap between standard loss characterisation under ideal conditions and real operating condition of state-of-the-art magnetic devices. To also emulate the two-dimensional flux loci arising in the non-oriented steel laminations in the stator core of a rotating machine.

  5. To facilitate take up of the results by industry, NMIs and standardisation bodies (IEC TC 68 and ISO/TC201/SC 9) by providing updates on magnetic imaging techniques and good practice guides for improved traceable magnetic loss measurements at higher frequency and induction, allowing for an evolution of the current IEC 60404 standards for loss measurement reflecting up-to-date industrial needs.


Progress beyond the state of the art and results

Power losses with standard measurement setups:

To date a number of intercomparisons involving NMIs and stakeholders have been performed only at 50 Hz, but modern electrical machines are excited at higher induction and higher frequencies. This project will extend the frequency and induction range of traceable and validated loss measurements by performing: a round robin test between Epstein frame and single sheet tester (SST) at 50 Hz and 400 Hz; and a new Epstein round robin test up to 10 kHz. A good practice guide will be produced, providing details on the measurement of power losses in non-oriented and grain-oriented steel sheets at frequencies ranging from DC up to 10 kHz using standard measurement setups at room temperature. The guide will be shared with the stakeholders, end users and the IEC TC 68 committee.

Power losses under operating temperature conditions:

At present all magnetic loss calibration measurements at European NMIs and stakeholders are only carried out at 23° ± 5°, while electrical machines may operate at temperatures exceeding 100 °C, where saturation magnetisation, anisotropy and electrical conductivity are reduced. This project will develop and validate a new metrological infrastructure for Epstein frame measurements at temperatures up to 155 °C, to match the typical operating temperatures of electric motors. The results of the round robin tests will be discussed with the stakeholders and will be communicated to the to the IEC TC 68 through a good practice guide.

Alternating power losses in thin sheets up to the MHz range:

Alternating power losses can be accurately measured and modelled only under sinusoidal flux conditions, but in many modern electrical machines a very high harmonic content and skin effects are both present. This project will provide and apply a comprehensive approach to physically based wideband loss modelling in the presence of skin effects. This will enable improved loss prediction under arbitrary flux waveforms up to the MHz range, on the basis of data measured under sinusoidal flux conditions. The analysis will be supported by fluxmetric measurements, and by an interdisciplinary study of domain wall motion in amorphous materials and in thin GO sheets using scanning microscopy and magneto-optical experimental techniques.

Two-dimensional magnetisation and power losses:

To date several experimental techniques are available at selected NMIs and stakeholders for the determination of 2D losses, but no measurement standard has been established. In order to bridge the gap between standard loss characterisation under ideal conditions and real operating condition of state-of-the-art magnetic devices. This project will use a comprehensive experimental and modelling approach which will compare one- and two-dimensional measurements at frequencies up to 400 Hz with physical models. taking into account the non-uniform flux profiles due to the skin effect. Details of the performed 2D measurements and modelling and will be circulated among the stakeholders and to IEC TC 68 for further discussion and possible standards development.

Standards and end-users:

The measurement of magnetic losses in steel sheets of magnetically soft materials is regulated at the international level by a number of IEC standards. The data collected according to these standards and from additional interdisciplinary experimental techniques are the key ingredients in the study of the energy losses in soft magnetic materials using different modelling and theoretical approaches. This project will go beyond the current state-of-the-art by providing a necessary update to the standard loss measurement techniques at the European NMIs and stakeholder laboratories, reducing the expanded uncertainty, increasing the temperature range, increasing the frequency range, and increasing the peak induction, and by extending the analysis of losses to the presence of eddy currents and complex harmonic content. The results of these activities will be made available to end users through good practice guides, open access peer-reviewed scientific publications, and by providing input to IEC TC 68 and other international standardisation bodies.


Impact

Impact on industrial and other user communities

The outcomes of this project will benefit the power generation and supply industry; the transport sector; the machinery and metal products industries, leading to an increased energy conversion efficiency in utility transformers, high performance generators (i.e. wind and hydroelectric) and motors including aerospace, electric cars, scooters and bicycles where a high efficiency is required. Novel smart-grid power distribution networks driven by renewable sources (wind, solar) as well as high power railway and aircraft/drone engines will require small size solid-state transformers operating at frequencies of 3 kHz or higher, and current measurement standards have not been yet validated at such frequencies. To date, electrical machine designers rely on insufficient or inadequate magnetic hysteresis and loss data obtained at room temperature using standard characterisation techniques at 50 Hz only. New calibration and measurement services will be established and offered to relevant European industries, stakeholders and end users. Updated measurement procedures will be advertised to standardisation bodies for uptake by industrial partners and the definition of evolved or new standards. The projects’ results and outcomes will be circulated to industry and academia through participation in international meetings, articles in peer reviewed journals and through the circulation of good practice guides leading to an increased confidence in the use of experimental data for modelling of hysteresis and loss with noticeable improvements in electrical machine design.

Impact on the metrology and scientific communities

New and extended magnetic loss measurement procedures developed in the project will be made available to the stakeholders and end users through the project website and data repository, through reports to EURAMET TC-EM and CCEM, to the relevant IEC committee and through good practice guides and open-access scientific publications. This will enable academic, R&D and industrial labs to improve their loss measurement techniques. Reference samples produced as a result of the round robin comparisons will also be available for calibrations and thus will immediately support improved magnetic loss metrology research and development. New and extended metrology infrastructure for loss measurements at high temperatures developed and established at the participating NMIs will be made available to the metrological and scientific community. The project also addresses magneto optical surface characterisation under dynamic and elevated temperature conditions that have not been performed on electrical steel to date, as well as studies of the AC magnetic field penetration affected by the skin effect and by local structural defects in a wide frequency range from 50 Hz-10 kHz. The results obtained will provide parameters such as domain width and domain densities and additional information about flux penetration depths that will be used within the metrology and R&D communities as input parameters for extended magnetic modelling to improve the reliability and effectiveness of the loss and hysteresis models.

Impact on relevant standards

This project will support the implementation of the Ecodesign Directive 2009/125/EC, which provides consistent EU-wide rules for improving the environmental performance of products by setting out minimum mandatory requirements for energy efficiency, through the use of state-of-the-art loss measurement and hysteresis modelling techniques developed in the project. The consortium will promote the uptake of the project’s results within the standardisation community through the publication of good practice guides directed to end users. Partners regularly participate at the IEC, EURAMET TC-EM and CCEM committee meetings, are in contact with key active members of various national and international standardisation committees (CEI, ISO, IEC), and actively participate in the discussion, preparation, and comparisons devoted to upgrading of existing measuring standards and the development of new ones. In particular this project will directly provide input to the IEC TC 68 committee “Magnetic Alloys and Steels” for discussion and evolution on the current standards.

Longer-term economic, social and environmental impacts

Europe, with 500 production sites spread across 23 EU countries, is the second largest producer of steel in the world after China. Steel-making is the third largest EU industry, and closely linked to many downstream industries such as construction, automotive, electronics, mechanical and electrical engineering, where magnetic grade steel is used for the production and transformation of almost all of the distributed electric power, for industrial and household motors and now increasingly for the transport sector. The current global magnetic steel market has a value exceeding 20 G€/year and most soft magnetic steel production is located in the EU and Asia. Magnetic steel is used in Europe by more than 2500 transformer and electric motor manufacturers and producers. The state-of-the-art and metrologically validated measurement techniques and associated guidance developed in the project will support the characterisation of novel and more energy-efficient industrial steel products, helping Europe to maintain and expand its expertise and leadership in the production of special steel.

People’s health can be affected by (local) emissions from power plants, district heating and local residential heating systems, transport and industry. Electricity and heat generated by these facilities lead to increased air pollution such as NOx, SO2, small particulate matters (PM2.5) and CO2. The European Environmental Agency estimated that there were 403,000 deaths related to PM2.5 and 72,000 deaths related to NOx in 2012. By reducing energy consumption and implementing energy efficiency policies targeting industrial processes, some of this air pollution can be avoided including reducing emissions of PM2.5.

The cumulative energy savings associated with the implementation of the Ecodesign directive to be achieved between 2009 and 2020 were estimated to reach 2035 TWh, with additional energy savings of 100 TWh per year by 2030. The outcomes of this project which promotes more accurate and efficient magnetic steel testing measurement methods are expected to be used in the power generation and supply industry; the transport and aerospace sector; and the machinery and metal products industries, leading to an overall improved energy conversion efficiency. Additional energy savings connected to the design and construction of higher efficiency electric motors, transformers and power electronics devices, will also contribute to reaching the EU 32.5% efficiency target for 2030, defined by the EC Energy Efficiency Directive 2012/27/EU (amended 2018/2002).


List of publications

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***For all other JRPs***

Project start date and duration:


1/9/2020 - 36 months


Coordinator: Massimo Pasquale INRIM Tel:+39-011-3919820 E-mail:m.pasquale@inrim.it

Project website address: TBD




Internal Funded Partners:

  1. INRIM, Italy

  2. CMI, Czech Republic

  3. NPL, United Kingdom

  4. PTB, Germany

  5. TUBITAK, Turkey

External Funded Partners:

  1. CNRS, France

  2. IFW Dresden, Germany

  3. INNOVENT, Germany

  4. POLITO, Italy

  5. UNOTT, United Kingdom