A novel and coupled Electromagnetic and Electrothermal software for quench analysis of high field magnets

High-field REBCO magnets contain several coils with many turns. {For these magnets,} electro-thermal quench is an issue that magnet designers need to take into account. Thus, there is a need for fast and accurate software to numerically model the overall performance of full-scale magnets. High temperature superconductors can be modeled using different techniques for electro-magnetic (such as $H$-formulation and $A-V$ formulation) and thermal (finite element method) analysis. However, it takes a lot of time to model the electro-magnetic and electro-thermal behavior of superconductors simultaneously in a commercial software, especially for non-insulated or metal-insulated coils. We have developed a novel software programmed in C++, which performs coupled electro-magnetic and electro-thermal analysis using variational methods based on Minimum Electro-Magnetic Entropy Production (MEMEP) and Finite Difference, respectively. The developed software is applied to axi-symmetric fullscale magnets of more than 30 T field strength for transient design (thermal quench reliability), taking screening currents into account. We show that the magnets incorporating non-insulated coils {are more reiable against quench} than the metal insulated coils. Also, {realistic} cooling conditions at boundaries is essential for such simulations. The model developed can be used for a quick and complete electro-magnetic and electro-thermal analysis of superconducting high field magnets.Comment: Improved figures. Corrected tex

Multiphysics Modelling of the LHC Individually Powered Quadrupole Superconducting Circuits

In the LHC there are 131 different types of circuits connecting main bending magnets, magnets for beam focusing, dipole field correctors, or higher-order correctors. A total of 78 Individually Powered Quadrupole (IPQ) circuits are present in the LHC matching sections, operating either in 1.9 K superfluid helium or in boiling helium at 4.5 K. The superconducting circuits are composed of different elements, at different temperatures, in different materials, connected to each other in a multi-scale and multi-physics domain. The reason to generate and validate these models is driven by the necessity to realize an efficient and reliable multi-physics library of all the LHC superconducting circuits to simulate transients during normal operation of the machine, failure cases, and unexpected events. To simulate this complex scenario, the STEAM (Simulation of Transient Effects in Accelerator Magnets) framework was developed in the Machine Protection and Electrical Integrity Group (MPE) at CERN. The goal of STEAM is subdivided these complex phenomena into sub-problem and solve them with validated tools. For this reason, it contains in-house developed programs used to model transients in superconducting circuits. Once the electrical circuit and the finite element models are generated (thanks to the software packages for the semi-automatic generation) the hierarchical co-simulation framework, provide a common interface to run cooperative simulations of the validated models. These cooperative simulations allow the exchanging of information between several models, ensuring the consistency of the results due to the co-simulation algorithm. During this thesis the main programs used are: PSpice (a commercial tool used to generate the electrical circuit model), STEAM-LEDET (a STEAM in-house tool, used to generate the electro-thermal magnet model), and STEAM-COSIM (used to combine both models, PSpiceand STEAM-LEDET, in a cooperative simulation)

Overview of Sensitivity Analysis Methods Capabilities for Traction AC Machines in Electrified Vehicles

© 2021 The Author(s). This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/.A robust design in electrified powertrains substantially helps to enhance the vehicle's overall efficiency. Robustness analyses come with complexity and computational costs at the vehicle level. The use of sensitivity analysis (SA) methods in the design phase has gained popularity in recent years to improve the performance of road vehicles while optimizing the resources, reducing the costs, and shortening the development time. Designers have started to utilize the SA methods to explore: i) how the component and vehicle level design options affect the main outputs i.e. energy efficiency and energy consumption; ii) observing sub-dependent parameters, which might be influenced by the variation of the targeted controllable (i.e. magnet thickness) and uncontrollable (i.e. magnet temperature) variables, in nonlinear dynamic systems; and iii) evaluating the interactions, of both dependent, and sub-dependent controllable/uncontrollable variables, under transient conditions. Hence the aim of this study is to succinctly review recent utilization of SA methods in the design of AC electric machines (EM)s used in vehicle powertrains, to evaluate and discuss the findings presented in recent research papers while summarizing the current state of knowledge. By systematically reviewing the literature on applied SAs in electrified powertrains, we offer a bibliometric analysis of the trends of application-oriented SA studies in the last and next decades. Finally, a numerical-based case study on a third-generation TOYOTA Prius EM will be given, to verify the SA-related findings of this article, alongside future works recommendations.Peer reviewe

CLIQ Based Quench Protection of 16 [T] Nb3Sn Block-Coil Dipole Magnets for a Future Circular Collider

Protection of large high-field, high-energy accelerator magnets is very challenging with current technology. To avoid damage to the magnet coil by local or global overheating, the maximum temperature in the hot-spot of the magnet coil must be kept under certain levels depending on the materials used in the coil construction. The current state of the art technology seems unable to do so. A novel protection system for large superconducting magnets based on generating Inter Filament Coupling Loss through current oscillations in the magnet circuit is applied and simulated successfully for the Nb3Sn block-coil dipole magnet intended for use in a 100 [TeV] Future Circular Collider. The proposed protection system is able to keep the maximum temperature of the magnet coil during a quench below 350 [K] at nominal operating conditions, system parameters and geometry, and is shown to achieve a maximum temperature in the coil hot-spot as low as 260 [K] for the optimal protection system configuration. Several variations on the nominal coil geometry have been investigated, showing that an increase in inductance is detrimental while a reduction is beneficial from the point of view of the new protection system. Among the variations investigated are a graded coil and a coil with a larger aperture than the nominal geometry. The graded coil is found the most difficult to protect, while the larger aperture coil variant is the easiest to protect, with regards to the hot-spot temperature. A large parameter space has been investigated, and the most influential parameters are found to alter the hot-spot temperature by 50 [K], while the least influential by 10 [K] when moving away from their respective nominal values. Most influential are the electrical configuration of the protection system, the non-Copper content of the superconducting strands and the coil geometry. Least influential are the residual resistivity ratio and filament twist pitch. Taking the internal voltages to ground in the coil during application of the new protection system into account, the graded coil must be discarded completely, as turn-to-turn voltages can reach several hundred volt. The reduced inductance variants, therein the larger aperture one, proves the optimal also with respect to voltage: the turn-to-turn voltages are kept well below 100 [V], while the inter-layer voltage, critical for the application of the new protection system, only barely exceeds 1 [kV]

CLIQ Based Quench Protection of 16 [T] Nb3Sn Block-Coil Dipole Magnets for a Future Circular Collider

Protection of large high-field, high-energy accelerator magnets is very challenging with current technology. To avoid damage to the magnet coil by local or global overheating, the maximum temperature in the hot-spot of the magnet coil must be kept under certain levels depending on the materials used in the coil construction. The current state of the art technology seems unable to do so. A novel protection system for large superconducting magnets based on generating Inter Filament Coupling Loss through current oscillations in the magnet circuit is applied and simulated successfully for the Nb3Sn block-coil dipole magnet intended for use in a 100 [TeV] Future Circular Collider. The proposed protection system is able to keep the maximum temperature of the magnet coil during a quench below 350 [K] at nominal operating conditions, system parameters and geometry, and is shown to achieve a maximum temperature in the coil hot-spot as low as 260 [K] for the optimal protection system configuration. Several variations on the nominal coil geometry have been investigated, showing that an increase in inductance is detrimental while a reduction is beneficial from the point of view of the new protection system. Among the variations investigated are a graded coil and a coil with a larger aperture than the nominal geometry. The graded coil is found the most difficult to protect, while the larger aperture coil variant is the easiest to protect, with regards to the hot-spot temperature. A large parameter space has been investigated, and the most influential parameters are found to alter the hot-spot temperature by 50 [K], while the least influential by 10 [K] when moving away from their respective nominal values. Most influential are the electrical configuration of the protection system, the non-Copper content of the superconducting strands and the coil geometry. Least influential are the residual resistivity ratio and filament twist pitch. Taking the internal voltages to ground in the coil during application of the new protection system into account, the graded coil must be discarded completely, as turn-to-turn voltages can reach several hundred volt. The reduced inductance variants, therein the larger aperture one, proves the optimal also with respect to voltage: the turn-to-turn voltages are kept well below 100 [V], while the inter-layer voltage, critical for the application of the new protection system, only barely exceeds 1 [kV]

Small business innovation research. Abstracts of 1988 phase 1 awards

Non-proprietary proposal abstracts of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA are presented. Projects in the fields of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robots, computer sciences, information systems, data processing, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered

Non-linear Model Predictive Control for cooling strings of superconducting magnets using superfluid helium

En cada uno de los ocho arcos del Gran Colisionador de Hadrones (LHC) de 27 km de circunferencia, largas cadenas de imánes superconductores de 2.5 km se enfrian con helio II superfluido a 1.9 K. La estabilización de la temperatura es un problema de control retador debido a complejas dinámicas no lineales de la temperatura de los imanes y la presencia de múltiples restricciones operativas. No-linealidades fuertes y tiempos muertos variables de la dinámica se originan en la conductividad de calor eficaz de superfluido dependiendo fuertemente de flujo de calor y pueden variar hasta tres órdenes de magnitud dentro de la gama de posibles condiciones operativas. Con el fin de mejorar la estabilización de la temperatura, se ha realiado una demostración con un Controlador Predictivo No-lineal económico (NMPC) con retroalimentación de salida que se presenta en esta tesis. El controlador se basa en un modelo numerico de primeros principios y de parámetros distribuidos, novedoso y complejo, para la dinámica de la temperatura en un subsector del LHC de 214 m de largo. El modelo se caracteriza por el muy bajo costo computacional de la simulación, necesario en control de procesos avanzado basado en optimización en tiempo real. Se presenta un análisis exhaustivo de los procesos físicos termo-hidráulicos que rigen la dinámica de temperatura, incluido la revisión de programas de I+D relacionados. El análisis explica las principales características de la dinámica de temperatura y ha sido el punto de partida para el desarrollo del modelo y la estrategia de control. También se describen las configuraciones experimentales utilizadas para identificar la dinámica y los parámetros del modelo de este sistema criogénico superfluido único. A través de la tesis, destaco los métodos prácticos utilizados para lograr la factibilidad de tiempo real del controlador, incluyendo: 1) aproximaciones, manejo de rigidez y ecuaciones algebraicas en el modelado y simulación, 2) la aplicación del estimador de estado híbrido Luenberger Observer - Mover Horizonte Estimación que permite el control de retroalimentación de salida a un costo muy bajo de computación, 3) parametrización de las trayectorias de variables optimizadas que reduce significamente el número de variables optimizados, 4) la aproximación del problema de optimización no-lineal original con restricciones de desigualdad usando uno con restricciones de desigualdad tipo caja que es mucho más fácil de resolver y 5) la aplicación de un solo paso de un método Quasi-Newton para el problema de optimización con restricciones tipo caja específico que se resuelve repetidamente en un controlador basado en la optimización. Se presentan dos configuraciones NMPC para la estabilización de la temperatura de los imanes sobre un sub-sector del LHC de 214 m de largo: 1) que manipula dos válvulas de control, probado experimentalmente en el LHC, y 2) que manipula las dos válvulas y 12 calentadores eléctricos, probado en simulaciones. Ambas configuraciones son factibles en tiempo real y presentan un excelente funcionamiento robusto en amplia gama de condiciones de operación, validando así tanto el modelo de parámetros distribuidos y el NMPC en linea con realimentación de salida basado en un modelo complejo de primeros principiosDepartamento de Ingeniería de Sistemas y Automátic

Wind turbine drivetrains:State-of-the-art technologies and future development trends

This paper presents the state-of-the-art technologies and development trends of wind turbine drivetrains – the system that converts kinetic energy of the wind to electrical energy – in different stages of their life cycle: design, manufacturing, installation, operation, lifetime extension, decommissioning and recycling. Offshore development and digitalization are also a focal point in this study. Drivetrain in this context includes the whole power conversion system: main bearing, shafts, gearbox, generator and power converter. The main aim of this article is to review the drivetrain technology development as well as to identify future challenges and research gaps. The main challenges in drivetrain research identified in this paper include drivetrain dynamic responses in large or floating turbines, aerodynamic and farm control effects, use of rare-earth material in generators, improving reliability through prognostics, and use of advances in digitalization. These challenges illustrate the multidisciplinary aspect of wind turbine drivetrains, which emphasizes the need for more interdisciplinary research and collaboration

Engineering Properties of Superconducting Materials

Plastic (and microplastic) pollution has been described as one of the greatest environmental challenges of our time, and a hallmark of the human-driven epoch known as the Anthropocene. It has gained the attention of the general public, governments, and environmental scientists worldwide. To date, the main focus has been on plastics in the marine environment, but interest in the presence and effects of plastics in freshwaters has increased in the recent years. The occurrence of plastics within inland lakes and rivers, as well as their biota, has been demonstrated. Experiments with freshwater organisms have started to explore the direct and indirect effects resulting from plastic exposure. There is a clear need for further research, and a dedicated space for its dissemination. This book is devoted to highlighting current research from around the world on the prevalence, fate, and effects of plastic in freshwater environments