Étude et conception d'une machine supraconductrice à modulation de flux pour application aéronautique

As part of the fight against climate change, the aeronautics industry has set itself the goal of becoming totally carbon neutral by 2050. To achieve this, the use of disruptive technologies is necessary to reduce the emissions of this fast-growing sector. Among these technologies, we find electrification, but its deployment requires high specific power electrical machines. In this context, superconductivity can be a way of improving electrical machines thanks to the high current densities and intense magnetic fields that can be generated with superconducting materials. The main drawback of this technology is the need to operate at cryogenic temperatures. However, the prospect of aircraft using liquid hydrogen as a fuel, transported at -253°C, presents a synergy with superconductivity. It is in this context that the work of this thesis is placed, which aims to study the use of high critical temperature superconducting materials for the development of a high specific power superconducting engine employing an original topology called "flux modulation machine". This machine structure has been studied for several years at the University of Lorraine within the Groupe de Recherche en Énergie Électrique de Nancy (GREEN), the laboratory in which this thesis was carried out. The work reported in this manuscript is part of a CIFRE agreement with the company SAFRAN. In order to allow the study of this machine, this thesis includes two chapters dedicated to the semi-analytical electromagnetic modelling of an axial flux modulation machine. The objective of this model is to allow a fast and accurate calculation of the torque and losses of a machine. The use of this model in the following chapter leads to the electromagnetic dimensioning of a 260 kW demonstrator. This design also takes into account the various technical and logistical constraints encountered. A fifth chapter details the ongoing construction of the demonstrator and its mechanical and cryogenic structure. Finally, the last chapter of this manuscript deals with the extrapolation of the experimental results in order to evaluate the potential performances of flux modulation machines at higher power.Dans le cadre de la lutte contre le changement climatique, l'industrie aéronautique s'est fixé pour objectif la neutralité carbone totale en 2050. Pour cela, l'emploi de technologies de rupture est nécéssaire pour réduire les émissions de ce secteur en forte croissance. Parmi ces technologies, on retrouve l'électrification mais dont le déploiement nécessite de disposer de machines électriques à forte puissance spécifique. Dans ce contexte la supraconductivité peut être une voie d'amélioration pour les machines électriques grâce aux fortes densités de courant ainsi qu'aux champs magnétiques intenses qu'il est possible de générer avec les matériaux supraconducteurs. L'inconvénient principal de cette technologie est la nécessité de fonctionner à des températures cryogéniques. Cependant, la perspective de l'emploi par les avions de l'hydrogène liquide comme carburant, transporté à -253 °C, présente une synergie avec la supraconductivité. C'est dans ce cadre que se placent les travaux de cette thèse qui a pour but d'étudier l'utilisation des matériaux supraconducteurs à haute température critique pour le développement d'un moteur supraconducteur à haute puissance spécifique employant une topologie originale appelée « machine à modulation de flux ». Cette structure de machine est étudiée depuis plusieurs années à l'Université de Lorraine au sein du Groupe de Recherche en Énergie Électrique de Nancy (GREEN), laboratoire dans lequel cette thèse s'est déroulée. Les travaux relatés dans ce manuscrit interviennent dans le cadre d'une convention CIFRE avec l'entreprise SAFRAN. Afin de permettre l'étude de cette machine, ce mémoire comporte deux chapitres dédiés à la modélisation électromagnétique semi-analytique d'une machine à modulation de flux axiale. L'objectif de ce modèle est de permettre un calcul rapide et précis du couple et des pertes d'une machine. L'utilisation de ce modèle dans le chapitre suivant permet d'aboutir au dimensionnement électromagnétique d'un démonstrateur de 260 kW. Ce dimensionnement tient en outre compte des différentes contraintes techniques et logistiques rencontrées. Un cinquième chapitre détaille la construction en cours du démonstrateur et sa structure mécanique et cryogénique. Enfin le dernier chapitre de ce manuscrit porte sur l'extrapolation des résultats expérimentaux dans le but d'évaluer les performances potentielles des machines à modulation de flux à plus forte puissance

Study of the current limiting capacity of 2G HTS tapes

International audienc

Study of the current limiting capacity of 2G HTS tapes

International audienc

Critical current density function of the position in a commercial REBaCuO bulk

International audienceAdvances in the melt-growth synthesis technique for preparing superconducting REBaCuO bulks allow the production and commercialisation of single crystals with a diameter of about 10 cm. This is in close agreement with the development of new applications such as electric motors where superconducting bulks are used as trapped field magnets or magnetic screens [1], [2]. It is then crucial to determine the superconducting properties such as critical temperature, critical current density and irreversible magnetic field, which is usually done using MPMS-SQUID on a millimetre size sample. In this study, the characterisation of a 10 cm wide commercial bulk machined for use as a magnetic shield is presented, see Fig. 1. 24 orthorhombic samples were extracted at different positions from the centre of the bulk, prepared and measured on a 14 T MPMS with a VSM head. A comparison of the superconducting properties of each sample will be presented together with the trapped field measurements performed on 10 other wide REBaCuO bulks. This will provide an opportunity to discuss the state of the art of this technology and its possible future development and will highlight the need to measure superconducting properties in different positions. Fig. 1: Magnetic flux density map measured on the surface of a REBaCuO bulk after magnetisation under 300 mT using a permanent magnet. References [1] Dorget, R. et al. Design of a 500 kW partially superconducting flux modulation machine for aircraft propulsion

Critical current density function of the position in a commercial REBaCuO bulk

International audienceAdvances in the melt-growth synthesis technique for preparing superconducting REBaCuO bulks allow the production and commercialisation of single crystals with a diameter of about 10 cm. This is in close agreement with the development of new applications such as electric motors where superconducting bulks are used as trapped field magnets or magnetic screens [1], [2]. It is then crucial to determine the superconducting properties such as critical temperature, critical current density and irreversible magnetic field, which is usually done using MPMS-SQUID on a millimetre size sample. In this study, the characterisation of a 10 cm wide commercial bulk machined for use as a magnetic shield is presented, see Fig. 1. 24 orthorhombic samples were extracted at different positions from the centre of the bulk, prepared and measured on a 14 T MPMS with a VSM head. A comparison of the superconducting properties of each sample will be presented together with the trapped field measurements performed on 10 other wide REBaCuO bulks. This will provide an opportunity to discuss the state of the art of this technology and its possible future development and will highlight the need to measure superconducting properties in different positions. Fig. 1: Magnetic flux density map measured on the surface of a REBaCuO bulk after magnetisation under 300 mT using a permanent magnet. References [1] Dorget, R. et al. Design of a 500 kW partially superconducting flux modulation machine for aircraft propulsion

Critical current density function of the position in a commercial REBaCuO bulk

International audienceThe progress of the melt growth synthesis technique for preparing superconducting REBaCuO bulks allows the production and commercialization of a single crystal with a diameter of 10 cm. This is in good agreement with the development of new applications such as electrical motors where superconducting bulks are used as trapped field magnets or magnetic shields [1], [2]. It is then crucial to determine the superconducting properties such as the critical temperature, critical current density and irreversible magnetic field which is commonly done with the help of an MPMS-SQUID on a millimeter-size sample. However, the inhomogeneity of performances has been reported on a bulk [3], which highlights the necessity to measure the critical properties in multiple positions along the sample radius either in a grain sector or along a grain sector boundary.We propose a similar work with a characterization carried out on a 10 cm wide commercial bulk after machining for use as magnetic shields [1]. 24 rectangular samples have been extracted in a different position from the bulk’s center, prepared and measured on a 14 T MPMS with a VSM head. Then a comparison of the superconducting properties of each sample will be presented along with trapped field measurement done on 10 others wide GdBaCuO bulks. Finally, this will allow a discussion on the readiness of this technology and its possible future development and it will point out the necessity to measure the superconducting properties in different positions.[1]R. Dorget et al., « Design of a 500 kW partially superconducting flux modulation machine for aircraft propulsion », J. Phys. Conf. Ser., july 2021.[2]R. Dorget et al., « Review on the Use of Superconducting Bulks for Magnetic Screening in Electrical Machines for Aircraft Applications », Materials, jan. 2021.[3]V. Antal et al., « Relationship between local microstructure and superconducting properties of commercial YBa2Cu3O7- δ bulk », Supercond. Sci. Technol., févr. 2020

Critical current density function of the position in a commercial REBaCuO bulk

International audienceThe progress of the melt growth synthesis technique for preparing superconducting REBaCuO bulks allows the production and commercialization of a single crystal with a diameter of 10 cm. This is in good agreement with the development of new applications such as electrical motors where superconducting bulks are used as trapped field magnets or magnetic shields [1], [2]. It is then crucial to determine the superconducting properties such as the critical temperature, critical current density and irreversible magnetic field which is commonly done with the help of an MPMS-SQUID on a millimeter-size sample. However, the inhomogeneity of performances has been reported on a bulk [3], which highlights the necessity to measure the critical properties in multiple positions along the sample radius either in a grain sector or along a grain sector boundary.We propose a similar work with a characterization carried out on a 10 cm wide commercial bulk after machining for use as magnetic shields [1]. 24 rectangular samples have been extracted in a different position from the bulk’s center, prepared and measured on a 14 T MPMS with a VSM head. Then a comparison of the superconducting properties of each sample will be presented along with trapped field measurement done on 10 others wide GdBaCuO bulks. Finally, this will allow a discussion on the readiness of this technology and its possible future development and it will point out the necessity to measure the superconducting properties in different positions.[1]R. Dorget et al., « Design of a 500 kW partially superconducting flux modulation machine for aircraft propulsion », J. Phys. Conf. Ser., july 2021.[2]R. Dorget et al., « Review on the Use of Superconducting Bulks for Magnetic Screening in Electrical Machines for Aircraft Applications », Materials, jan. 2021.[3]V. Antal et al., « Relationship between local microstructure and superconducting properties of commercial YBa2Cu3O7- δ bulk », Supercond. Sci. Technol., févr. 2020

Trapped magnetic field characteristics of MgB2 bulk with different additive contents and MgB2 bulk with different types of additives by pulse magnetization

International audienceWhen the MgB2 bulk body is magnetized by the pulse magnetizing method, the MgB2 bulk can take the role of a pseudo permanent magnet. However, it was confirmed that the temperature at which MgB2 is expected to be used is close to the critical temperature (TC) of MgB2 and the specific heat is small, so that the heat generated by the pulse magnetizing method causes flux jump and the trapped magnetic field performance deteriorates. In this study, pulse magnetizing was performed on different samples to verify and consider changes in the trapped magnetic field performance. As the sample, the sample obtained by changing the amount of titanium added was synthesized by uniaxial hot pressing and the sample synthesized by spark plasma sintering (SPS). Figure (a) shows a comparison of the trapped magnetic fields of the samples synthesized by the uniaxial hot press. From Fig. (A), it was shown that the capture magnetic field performance may be improved or deteriorated by the composition ratio of the material, the addition of impurities, and the method of synthesizing the bulk material

Review on the Use of Superconducting Bulks for Magnetic Screening in Electrical Machines for Aircraft Applications

High-Temperature Superconductors (HTS) considerably accelerate the development of superconducting machines for electrical engineering applications such as fully electrical aircraft. This present contribution is an overview of different superconducting materials that can be used as magnetic screens for the inductor of high specific power electrical machines. The impact of the material properties, such as the critical temperature (Tc) and the critical current density (Jc), on the machine performances is evaluated. In addition, the relevance to flux modulation machines of different HTS bulk synthesis methods are addressed

Trapped magnetic field characteristics of MgB2 bulk with different additive contents and MgB2 bulk with different types of additives by pulse magnetization

International audienceWhen the MgB2 bulk body is magnetized by the pulse magnetizing method, the MgB2 bulk can take the role of a pseudo permanent magnet. However, it was confirmed that the temperature at which MgB2 is expected to be used is close to the critical temperature (TC) of MgB2 and the specific heat is small, so that the heat generated by the pulse magnetizing method causes flux jump and the trapped magnetic field performance deteriorates. In this study, pulse magnetizing was performed on different samples to verify and consider changes in the trapped magnetic field performance. As the sample, the sample obtained by changing the amount of titanium added was synthesized by uniaxial hot pressing and the sample synthesized by spark plasma sintering (SPS). Figure (a) shows a comparison of the trapped magnetic fields of the samples synthesized by the uniaxial hot press. From Fig. (A), it was shown that the capture magnetic field performance may be improved or deteriorated by the composition ratio of the material, the addition of impurities, and the method of synthesizing the bulk material