6,725 research outputs found
Eddy-Current Losses evaluation in hairpin wound motor fed by PWM Inverter
No full textThis paper presents different approaches proposed to evaluate eddy-current losses in hairpin wound motor fed by pulse width modulated inverter, underlining strengths and weaknesses of everyone and applying them, as test-case, to a 200kW induction motor designed for a premium electric vehicle. The first three approaches are based on the finite element analysis: the first, the more accurate one, use a transient analysis that request long execution time and high memory usage, the second is based on tool that permits rapidly to evaluate the steady state conditions imposing a sinewave current and the third uses a single-slot simplified model. The fourth approach proposes a rapid monodimensional analytic method based on hypotheses that permit to consider the superposition effects of the Eddy Current Losses of every current harmonic component. The fifth approach makes uses of the proposed analytic method by leveraging a rapid investigation of current harmonic content due to pulse width modulation based on a lumped parameter motor model.
In addition, the paper discusses important considerations about the use of the hairpin technology fed by pulse width modulation that can be drawn from the analysis of the obtained result
Popescu (Teodor M.) Enciclica patriarhilor ortodocsi delà 1848
No full textJanin Raymond. Popescu (Teodor M.) Enciclica patriarhilor ortodocsi delà 1848. In: Échos d'Orient, tome 35, n°184, 1936. p. 496
T. R. Popescu et M. Pascu, Càsàtoria, familia si dreptul
No full textT. R. Popescu et M. Pascu, Càsàtoria, familia si dreptul. In: Revue internationale de droit comparé. Vol. 17 N°3, Juillet-septembre 1965. pp. 804-805
Efficient Calculation of PWM AC Losses in Hairpin Windings for Synchronous BPM Machines
No full textThis paper focuses on the alternative current (AC) losses in hairpin winding variation due to the skin and proximity effects in synchronous brushless permanent magnet machines when supplied from a pulse width modulation (PWM) inverter. Based on a motor used in a 200kW electrical drive unit, three main methodologies are investigated to demonstrate the importance of these additional losses and how it is possible to take them into account when modeling the electrical machine performance. A more rigorous approach and two more time-efficient ones are utilized for the purpose, showing powerful ways of taking into consideration the pulse width modulation induced eddy currents losses in stator conductors since the early stages of the design process. A reduction ratio of 30:1 in computation time gives the proposed methodologies great merit not only in modeling single operating points, but over the full torque-speed characteristic, efficiency maps, and drive/duty-cycles analyses
Hairpin Windings for Traction Machines: Analysis and Comparison
No full textThis work investigates circulating currents and additional losses in hairpin windings with multiple parallel paths when a weak symmetry pattern is adopted. The theoretical rules for designing hairpin windings may lead to configurations not completely preventing parasitic currents in the parallel branches, especially in heavy saturation conditions. Often, the proposed configurations in the literature present a weak symmetry between the parallel branches. This paper considers a typical hairpin winding configuration to compute the actual currents in the parallel paths. For this purpose, machine models are driven by an external three-phase circuit and finite element analyses are carried out. The main goal is to explain the causes of circulating currents. The analysis is repeated using different rotor topologies and keeping respectively the same stator design, overall machine volume and hairpin winding pattern to look into the different effects in windings induced by parasitic currents
BOOK REVIEW ON THE CITY AND THE URBAN COMPETITION, AUTHOR: IRINA POPESCU
No full textThe book “The city and the urban competition / Orasul si competitia urbana”, written by Irina Popescu, has recently been published at Economic Publishing House of Bucharest, Romania. The book is structured in 4 parts and it is very rich in concepts, ideas, theories, principles and comparative studies, representing an important contribution of the author to the development of the literature concerning the study of the city.urban competition, urban system
Integrating games into the classroom: towards new teachership
No full textPublisher statement: This chapter appears in New Pedagogical Approaches in Game Enhanced Learning: Curriculum Integration, edited by S. de Freitas, M. Ott, M.M. Popescu & I. Stanescu. Copyright, 2013, IGI Global, www.igi-global.com. Posted by permission of the publisher
Beaty Popescu : This Green Bag
No full textHorne discusses Popescu's works from 1987 to 1992 involving natural objects embedded within layers of paper; the author treats themes such as the interior/exterior dichotomy and analogies with food and digestive organs. Artist's statement. Biographical notes. 28 bibl. ref
Color Sensors based on amorphous silicon
No full textStiebig H, Knipp D. Color Sensors based on amorphous silicon. In: Popescu M, ed. “Physics and Application of disordered materials. INOE; 2002: 323-348
- …
