Digital Current Controller with Error-Free Feedback Acquisition and Active Resistance

Digital current controllers have the key impact on the performance of grid-side converters and ac drives. The voltage disturbances are commonly suppressed by enhancing the controller with an inner active resistance feedback. In cases where the switching noise and parasitic oscillations introduce sampling errors, conventional sampling is replaced by the oversampling-based error-free feedback acquisition which derives the average of the measured currents over the past switching period. The time delay introduced into the feedback path creates difficulties in designing the current controller with the active resistance. In this paper, we introduce a novel structure of the current controller which includes the error-free sampling and the active resistance feedback. Devised structure improves the disturbance rejection by extending the range of permissible values of the active resistance. Controller structure is based on the internal model principles and it maintains the input step response unaffected. The paper comprises analytical design, the gain setting procedure, computer simulation and experimental results obtained from an experimental setup with a three-phase inverter, digital controller, and a permanent magnet synchronous motor

Enhanced Active Disturbance Rejection Current Controller for Permanent Magnet Synchronous Machines Operated at Low Sampling Time Ratio

Recently, Active Disturbance Rejection Control (ADRC) Scheme has been widely used for current regulation in AC drive systems owing to its robustness to system uncertainties and its high disturbance-rejection capability. However, it has not been considered as an option for high-speed drives usually operated at limited switching and sampling frequencies. Therefore, this paper thoroughly analyses and discusses the effects of high operating speed, modulation, and computational delays on the conventional ADRC. Based on this analysis, an enhanced ADRC for the current control is proposed to operate the drive system at low sampling time ratio with high robustness to the internal and external disturbances. Effect of model uncertainties on the proposed scheme has also been analytically analyzed and reported. Comprehensive simulation and experimental results have been presented to demonstrate the improved performance of the proposed ADRC scheme and to support the analytical studies

Bulletin of scientific and art research : annual report for 2018

The SASA Fund allotted the available resources for the following purposes: scientific and art research projects, scientific publications, international scientific cooperation, the organization of scientific meetings, participation of SASA members and their associates in scientific meetings in the country and abroad, acquisition of scientific literature and other purposes under the SASA Scientific and Art Research Programme. In 2018, the SASA Scientific and Art Research Programme contained 28 projects in the fields of mathematics, physics and earth sciences, 20 in the fields of chemical and biological sciences; 13 in the fields of technical and technological sciences; 28 in the field of medical sciences, 12 in the fields of language and literature; 16 in the field of social sciences; 25 in the field of historical sciences, and 8 in the fields of visual arts and music. During the year, the SASA published 52 editions, including 13 journal issues, 19 collections of papers, 13 catalogues, five monographs, two jubilee bibliographies and Volume XX of the SASA Dictionary, while 1,162 authors published 540 papers. The first-ever commercial Catalogue of the SASA Editions: 2016–2017–2018 (Katalog izdanja SANU: 2016–2017–2018) was prepared and published. In addition, 22 manuscripts were technically processed and prepared for publication; the make-up and cover design of six publications were finished. The SASA maintained regular contact with the National Library of Serbia concerning the preparation of a Cataloguing in Publication (CIP) record for all SASA editions. Fourteen manuscripts in the Serbian language underwent orthographic editing and 15 publications underwent proofreading, thus being prepared for publishing. The Serbian Academy of Sciences and Arts hosted the meeting of the COST (European Cooperation in Science and Technology) Action titled “Maximizing Impact of Research in Neurodevelopmental Disorders”. It was the first formal meeting of the COST Action which has so far been joined by about 50 researchers from 20 European countries. During 2018, two lecture cycles were held: “The Fascinating World of Nanoscience and Nanotechnology” (Fascinantni svet nanonauke i nanotehnologije) and “Geohazard in 21st Century Serbia: Knowledge Is the Best Bulwark Against the Elements” (Geohazard u Srbiji u 21. veku – Znanje je najbolji bedem protiv stihije), totalling 11 lectures. In 2018, at the proposal of the SASA Departments and SASA Executive Board, 12 lectures were held. Pursuant to the Decision of the Professional Council of the SASA Library, the SASA Library Day will be celebrated on 14 June. The SASA Library started working on this day, when it received the first books from Dimitrije Tirol. Its first librarian was Konstantin Bogdanović. The SASA Library Day was marked by the celebration honouring Aleksa Šantić. In 2018, the SASA Library organized 17 forums. It presented 18 books and 13 collections of papers by SASA members, SASA editions, as well as the research institutes and centres founded by the SASA. It staged 12 chamber exhibitions. Pursuant to the Decision of the Professional Council of the SASA Library, the SASA Library Day will be celebrated on 14 June. The SASA Library started working on this day, when it received the first books from Dimitrije Tirol. Its first librarian was Konstantin Bogdanović. The SASA Library Day was marked by the celebration honouring Aleksa Šantić. In 2018, the SASA Library organized 17 forums. It presented 18 books and 13 collections of papers by SASA members, SASA editions, as well as the research institutes and centres founded by the SASA. It staged 12 chamber exhibitions. The SASA Library also published the jubilee Bibliography of Academician Nikola Tasić’s Works, authored by Milena Obradović, and the sixth issue of the SASA Library Forum Almanac (Godišnjak “Tribina Biblioteke SANU”). The 293-page issue of the Almanac contains the presentations given at the forums in 2017. In 2018, the SASA Gallery staged eight thematic exhibitions on its premises: “Stojan Novaković and His Era” (Stojan Novaković i njegovo doba), “So, you are Uroš Predić?“ (Dakle, vi ste taj Uroš Predić), “35 Years of Petnica” (35 godina Petnice), “Mihailo Petrović Alas, the Founding Father of the Serbian School of Mathematics” (Mihailo Petrović Alas, rodonačelnik srpske matematičke škole), “Nedeljko Gvozdenović. On a Quest for Absolute Painting” (Nedeljko Gvozdenović. U potrazi za apsolutnim slikarstvom), “Roman Limes and Cities in Serbia” (Rimski limes i gradovi u Srbiji), 57th October Salon. “The Marvellous Cacophony” (57. Oktobarski salon. Čudo kakofonije), “Marko Čelebonović (1902-1986)”, Retrospective Exhibition (Marko Čelebonović /1902-1986/. Retrospektivna izložba). All exhibitions were accompanied by catalogues, lectures and expert guidance. Six catalogues were printed and one was prepared for printing. The exhibitions staged outside the SASA Gallery included: “SASA Art Collection – Academician Artists” (Umetnička zbirka SANU – likovni umetnici akademici), which toured Požarevac, Leskovac and Svilajnac, and “Olga Jevrić Exhibition – Sculptures” (Izložba Olga Jevrić – skulpture) in Užice. Seven new exhibitions were also prepared. In 2018, the Gallery of the Serbian Academy of Sciences and Arts organized 74 concerts within the relevant cycles. The concert-related activity of the SASA Gallery is headed by Academician Ivan Jevtić. During the year, the SASA Gallery of Science and Technology staged 15 exhibitions, supported by rich accompanying programmes. The names of these exhibitions were “Roma Tribulation in World War I” (Stradanje Roma u Prvom svetskom ratu); “Ivan Djaja. The Belgrade School of Physiology – from the Sorbonne to Belgrade” (Ivan Djaja. Beogradska škola fiziologije – od Sorbone do Beograda); “Brain Awareness Week 2018 – All Sides of Consciousness” (Nedelja svesti o mozgu – Sve strane svesti); “Traditional Architectural Heritage in the Area of the Stara Planina” (Tradicionalno arhitektonsko nasledje u regionu Stare planine); “The History of Toxicology” (Istorija toksikologije); THE POWER OF HERBS – The 70th Anniversary of the Institute for Medicinal Herb Research “Dr Josif Pančić” (MOĆ BILJA – povodom 70 godina rada Instituta za proučavanje lekovitog bilja “Dr Josif Pančić”); “This too Is Serbia, ’68 in Student” (I ovo je Srbija, ’68. u Studentu); “Archaeological Forensics – 20 Years of New Archaeological Invesigations of Vinča” (Forenzika drevnosti – 20 godina novih arheoloških istraživanja lokaliteta Vinča); “Serbian Lexicography from Vuk to the Present Day” (Srpska leksikografija od Vuka do danas); “Jovan Stejić, First Serbian Doctorof Medicine in Restored Serbia” (Jovan Stejić, prvi Srbin doktor medicine u obnovljenoj Srbiji); The Salonika Front, 1916-1918 (Solunski front 1916- 1918); World War One in Miniature (Prvi svetski rat u minijaturi), and ON ARCHITECTURE 2018 (O ARHITEKTURI 2018). The exhibitions were supported by the relevant catalogues (5) and rich accompanying programmes. In 2018, the SASA Archives enriched its holdings by numerous gifts. It finished processing Academician Vasa Čubrilović’s manuscript legacy and Patriarch German Andjelić’s legacy. The processing of Dragoljub Jovanović’s legacy will be finished during the first few months of 2019. The work on organizing the collection held in the Cabinet for Medals was carried out. The electronic Incoming Inventory of the Cabinet was prepared. All decorations were sorted out and placed into archival boxes in order to ensure better protection and facilitate handling. The Central Institute for Conservation conserved 169 decorations. More than 800 decorations were photographed and cataloguing was done in accordance with all museological processing rules. The website and digital presentation were created, and the biographies of all donors were written. The result of this work is the permanent exhibition of the Cabinet for Medals, which was opened on the Day of the Academy on 19 November 2018. During the past year, the SASA archivists catered to 223 researchers. The reference library of the SASA Archives was enriched by 70 new books.Ima izdanje na drugom jeziku: Билтен Фонда САНУ за истраживања у науци и уметности = ISSN 2466-428

Билтен Фонда САНУ за истраживања у науци и уметности за 2018.годину . Бр. 44

Фонд САНу за истраживања у науци и уметности је у 2018. години остварио укупни приход у износу од 52.500.000,00 динара, од министарства просвете, науке и технолошког развоја Републике србије (уг. бр. 1/19 од 19. марта 2018). министарство је уплату извршило у целини 30. марта 2018. године. Одлуку о расподели средстава за 2018. годину донео је управни одбор Фонда, на седници одржаној 3. маја 2018. године, на основу предлога и сугестија Академијиних одељења, и Извршног одбора САНуУ Фонд САНУ је уплаћена средства распоредио на следеће позиције: за научноистраживачке и пројекте у области уметности, објављивање научних публикација, међународну научну сарадњу, организовање научних скупова, учешће чланова САНУ и њихових сарадника на научним скуповима у земљи и иностранству, набавку научне литературе и за друге намене Програма научноистраживачких и уметничких активности САНУ. На ове намене утрошен је укупан износ уплаћених средстава, односно 52.500.000,00 динара.До броја 40 часопис је излазио под називом: Билтен Фонда за научна истраживања САНУ (ISSN 0352-2385)