Забезпечення ефективності індуктивної системи передачі енергії зі змінюваними умовами зв’язку

Жук, О. К. Забезпечення ефективності індуктивної системи передачі енергії зі змінюваними умовами зв’язку = Ensuring the efficiency of the inductive energy transmission system with variable connection conditions / О. К. Жук, Я. В. Дзисюк // Shipbuilding & Marine Infrastructure. – 2021. – № 1 (15). – С. 24–35.Анотація. У статті розглядаються загальні проблеми зарядки потужних літій-іонних акумуляторів у морських застосуваннях, зокрема на електричних поромах із нульовим рівнем викидів, за умови підзарядки до достатнього рівня енергії за короткий час кожного стикування, який становить лише 4–5 хв. Для таких застосувань найбільш прийнятне використання бездротової безконтактної індуктивної передачі енергії, що дозволяє виконувати безпечні та повністю автоматизовані операції підзарядки із кращим використанням обмеженого часу стикування, проте впровадження технології індуктивної зарядки у морському секторі вимагає врахування деяких особливостей і вирішення пов’язаних із ними технічних проблем: 1) на відміну від наземних транспортних засобів (електромобілів, електробусів, трамваїв) для суден потрібен значно вищий рівень потужності, що передається, тому морський індуктивний зарядний пристрій повинен мати номінальну потужність близько кількох одиниць мегават; 2) під час зарядки судно може переміщуватися відносно нерухомої частини зарядної системи через комбіновану дію вітру, хвиль і зміну осадки під час завантаження і вивантаження, тобто ефективність індуктивної зарядної системи повинна бути незалежною від зсуву і зміни взаємного розташування елементів індуктивного зв’язку (котушок), а також довжини повітряного проміжку між ними. Метою роботи є аналіз напрямів удосконалення сучасних індуктивних зарядних систем для акумуляторних морських суден шляхом пошуку принципів забезпечення інваріантності переданої потужності (зарядного струму) і показників енергоефективності зазначених систем до зміни умов індуктивного зв’язку. У статті розглянута послідовно-послідовна конфігурація компенсованої індуктивної зарядної системи з керованим інвертором напруги та діодним випрямлячем, запропоновано математичну модель системи та виконано її дослідження в частотній області. Вперше отримані та досліджені залежності енергетичних характеристик системи від робочої частоти. За результатами зазначених досліджень сформульовані нові принципи стабілізації переданої потужності (зарядного струму) і забезпечення одиничного коефіцієнта потужності у всьому діапазоні зміни коефіцієнта індуктивного зв’язку, що реалізуються за рахунок регулювання частоти при незмінній вихідній напрузі інвертора; одержані рекомендації щодо покращення енергоефективності шляхом використання нерезонансних режимів за умови зміни індуктивного зв’язку. Використання зазначених результатів дозволить зменшити необхідну встановлену потужність індуктивної зарядної системи, а отже, її вагу і габарити, та мінімізувати час зарядки акумуляторів електричних морських суден.Abstract. The general problems of charging powerful lithium-ion batteries in marine applications, in particular on zero-emission electric ferries, are considered, provided that they are charged to a sufficient energy level for a short time of each docking, which is only 4–5 minutes. For such applications, the most acceptable use of wireless contactless inductive energy transfer, which allows you to perform safe and fully automated charging operations with the best use of limited docking time. However, the introduction of inductive charging technology in the maritime sector requires taking into account some features and solving related technical problems: 1) in contrast to land vehicles (electric cars, electric buses, trams), ships require a much higher level of transmitted power, so the marine inductive charger must have a rated power of the order of a few megawatts; 2) during charging the vessel can move relative to the stationary part of the charging system due to the combined action of wind, waves and change of draft during loading and unloading, ie the efficiency of the inductive charging system must be independent of shift and change of mutual arrangement of inductive communication elements ( coils), as well as the length of the air gap between them. The purpose of this work is to analyze the areas of improvement of modern inductive charging systems for battery ships by finding the principles of invariance of transmitted power (charging current) and energy efficiency of these systems to change the conditions of inductive communication. The sequential-serial configuration of the compensated inductive charging system with a controlled voltage inverter and a diode rectifier is considered in the article, a mathematical model of the system is proposed and its research in the frequency domain is performed. For the first time, the dependences of the energy characteristics of the system on the operating frequency are obtained and investigated. According to the results of these studies, new principles of stabilization of transmitted power (charging current) and providing a single power factor in the entire range of changes in the inductive coupling, which are implemented by adjusting the frequency at constant output voltage of the inverter; received recommendations for improving energy efficiency through the use of non-resonant modes under the condition of changing the inductive coupling. The use of these results will reduce the required installed capacity of the inductive charging system, hence its weight and dimensions, and minimize the charging time of batteries of electric marine vessels

Present Status and Future Programs of the n_TOF Experiment

This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial License 3.0, which permits unrestricted use, distribution, and reproduction in any noncommercial medium, provided the original work is properly citedThe neutron time-of-flight facility n_TOF at CERN, Switzerland, operational since 2001, delivers neutrons using the Proton Synchrotron (PS) 20 GeV/c proton beam impinging on a lead spallation target. The facility combines a very high instantaneous neutron flux, an excellent time of flight resolution due to the distance between the experimental area and the production target (185 meters), a low intrinsic background and a wide range of neutron energies, from thermal to GeV neutrons. These characteristics provide a unique possibility to perform neutron-induced capture and fission cross-section measurements for applications in nuclear astrophysics and in nuclear reactor technology.The most relevant measurements performed up to now and foreseen for the future will be presented in this contribution. The overall efficiency of the experimental program and the range of possible measurements achievable with the construction of a second experimental area (EAR-2), vertically located 20 m on top of the n_TOF spallation target, might offer a substantial improvement in measurement sensitivities. A feasibility study of the possible realisation of the installation extension will be also presented

Ni-62(n,gamma) and Ni-63(n,gamma) cross sections measured at the n_TOF facility at CERN

The cross section of the Ni-62(n,gamma) reaction was measured with the time-of-flight technique at the neutron time-of-flight facility n_TOF at CERN. Capture kernels of 42 resonances were analyzed up to 200 keV neutron energy and Maxwellian averaged cross sections (MACS) from kT = 5-100 keV were calculated. With a total uncertainty of 4.5%, the stellar cross section is in excellent agreement with the the KADoNiS compilation at kT = 30 keV, while being systematically lower up to a factor of 1.6 at higher stellar temperatures. The cross section of the Ni-63(n,gamma) reaction was measured for the first time at n_TOF. We determined unresolved cross sections from 10 to 270 keV with a systematic uncertainty of 17%. These results provide fundamental constraints on s-process production of heavier species, especially the production of Cu in massive stars, which serve as the dominant source of Cu in the solar system.Peer reviewedFinal Accepted Versio

Experimental neutron capture data of 58Ni from the CERN n_TOF facility

The neutron capture cross section of 58 Ni was measured at the neutron time of flight facility n-TOF at CERN, from 27 meV to 400 keV neutron energy. Special care has been taken to identify all the possible sources of background, with the so-called neutron background obtained for the first time using high-precision GEANT4 simulations. The energy range up to 122 keV was treated as the resolved resonance region, where 51 resonances were identified and analyzed by a multilevel R-matrix code SAMMY. Above 122 keV the code SESH was used in analyzing the unresolved resonance region of the capture yield. Maxwellian averaged cross sections were calculated in the temperature range of κT = 5 - 100 keV, and their astrophysical implications were investigated

Fission Fragment Angular Distribution measurements of 235U and 238U at CERN n-TOF facility

This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. EJP Web of Conferences 111, 10002 (2016). DOI: http://dx.doi.org/10.1051/epjconf/201611110002. © 2016 The Authors. Published by EDP Sciences.Neutron-induced fission cross sections of 238U and 235U are used as standards in the fast neutron region up to 200 MeV. A high accuracy of the standards is relevant to experimentally determine other neutron reaction cross sections. Therefore, the detection effciency should be corrected by using the angular distribution of the fission fragments (FFAD), which are barely known above 20 MeV. In addition, the angular distribution of the fragments produced in the fission of highly excited and deformed nuclei is an important observable to investigate the nuclear fission process. In order to measure the FFAD of neutron-induced reactions, a fission detection setup based on parallel-plate avalanche counters (PPACs) has been developed and successfully used at the CERN-n-TOF facility. In this work, we present the preliminary results on the analysis of new 235U(n,f) and 238U(n,f) data in the extended energy range up to 200 MeV compared to the existing experimental data

Measurement of the U 238 (n,γ) cross section up to 80 keV with the Total Absorption Calorimeter at the CERN n-TOF facility

The radiative capture cross section of a highly pure (99.999%), 6.125(2) grams and 9.56(5)×10-4 atoms/barn areal density U238 sample has been measured with the Total Absorption Calorimeter (TAC) in the 185 m flight path at the CERN neutron time-of-flight facility n-TOF. This measurement is in response to the NEA High Priority Request list, which demands an accuracy in this cross section of less than 3% below 25 keV. These data have undergone careful background subtraction, with special care being given to the background originating from neutrons scattered by the U238 sample. Pileup and dead-time effects have been corrected for. The measured cross section covers an energy range between 0.2 eV and 80 keV, with an accuracy that varies with neutron energy, being better than 4% below 25 keV and reaching at most 6% at higher energies

GEANT4 simulation of the neutron background of the C6D6 set-up for capture studies at n_TOF

The neutron sensitivity of the C6D6 detector setup used at n_TOF facility for capture measurements has been studied by means of detailed GEANT4 simulations. A realistic software replica of the entire n_TOF experimental hall, including the neutron beam line, sample, detector supports and the walls of the experimental area has been implemented in the simulations. The simulations have been analyzed in the same manner as experimental data, in particular by applying the Pulse Height Weighting Technique. The simulations have been validated against a measurement of the neutron background performed with a natC sample, showing an excellent agreement above 1 keV. At lower energies, an additional component in the measured natC yield has been discovered, which prevents the use of natC data for neutron background estimates at neutron energies below a few hundred eV. The origin and time structure of the neutron background have been derived from the simulations. Examples of the neutron background for two different samples are demonstrating the important role of accurate simulations of the neutron background in capture cross-section measurements

Neutron-induced fission cross sections of Th 232 and U 233 up to 1 GeV using parallel plate avalanche counters at the CERN n_TOF facility

The neutron-induced fission cross sections of $^{232}$Th and $^{233}$U were measured relative to $^{235}$U in a wide neutron energy range up to 1 GeV (and from fission threshold in the case of $^{232}$Th, and from 0.7 eV in case of $^{233}$U), using the white-spectrum neutron source at the CERN Neutron Time-of-Flight (n_TOF) facility. Parallel plate avalanche counters (PPACs) were used, installed at the Experimental Area 1 (EAR1), which is located at 185 m from the neutron spallation target. The anisotropic emission of fission fragments were taken into account in the detection efficiency by using, in the case of $^{233}$U, previous results available in EXFOR, whereas in the case of $^{232}$Th these data were obtained from our measurement, using PPACs and targets tilted 45∘ with respect to the neutron beam direction. Finally, the obtained results are compared with past measurements and major evaluated nuclear data libraries. Calculations using the high-energy reaction models INCL++ and ABLA07 were performed and some of their parameters were modified to reproduce the experimental results. At high energies, where no other neutron data exist, our results are compared with experimental data on proton-induced fission. Moreover, the dependence of the fission cross section at 1 GeV with the fissility parameter of the target nucleus is studied by combining those (p,f) data with our (n,f) data on $^{232}$Th and $^{233}$U and on other isotopes studied earlier at n_TOF using the same experimental setup

Fission Fragment Angular Distribution measurements of 235U and 238U at CERN n_TOF facility

Neutron-induced fission cross sections of $^{238}$U and $^{235}$U are used as standards in the fast neutron region up to 200 MeV. A high accuracy of the standards is relevant to experimentally determine other neutron reaction cross sections. Therefore, the detection efficiency should be corrected by using the angular distribution of the fission fragments (FFAD), which are barely known above 20 MeV. In addition, the angular distribution of the fragments produced in the fission of highly excited and deformed nuclei is an important observable to investigate the nuclear fission process. In order to measure the FFAD of neutron-induced reactions, a fission detection setup based on parallel-plate avalanche counters (PPACs) has been developed and successfully used at the CERN-n_TOF facility. In this work, we present the preliminary results on the analysis of new $^{235}$U(n,f) and $^{238}$U(n,f) data in the extended energy range up to 200 MeV compared to the existing experimental data