1,720,985 research outputs found
Modal characterization of a PMSM using different experimental techniques
No full textIn this paper different modal techniques are adopted in order to characterize the vibro-acoustic behaviour of a Permant Magnet Synchronous Motor (PMSM) for automotive applications. In addition to a well-known Experimental Modal Analysis (EMA), the vibration response measurement during ramp (run-up test) is exploited to apply an Operating Deflection Shapes (ODS) and an Operational Modal Analysis (OMA). Specifically, since the electric motor response is characterized by many time orders an Order Base Modal Analysis (OBMA) is adopted to overcome the weaknesses of an OMA, such as”end-of-order” distortions. Pros and cons of each individual technique on the specific application of an electric motor are analysed and discussed. The complementary use of the presented methodologies provides a comprehensive modal analysis of the electric motor
Noise and vibration modelling of Permanent Magnet Synchronous Motors - a review
Get PDFThis paper provides an overview of current Noise Vibration and Harshness (NVH) challenges for the design of Permanent Magnet Synchronous Motors (PMSMs) for automotive applications. Particular attention is devoted to analytical and numerical methods utilized in NVH modelling. Electromagnetic force computation, motor structural modelling and acoustic emission calculation are reviewed focusing on NVH emissions. The literature reveals, as expected, that analytical methods are simpler than numerical ones, and are usually employed during the preliminary design stage. Numerical methods are adopted in the detailed design stage as the computational cost increases. PMSMs are selected for high performance and high efficiency motor drives, they are widely adopted in the actual transition to vehicle electrification. The paper provides guidelines for facing NVH design issues of PMSMs
COMPARISON OF MULTI-OBJECTIVE OPTIMISATION METHODS FOR THE DESIGN OF ELECTRIC MOTORS
No full textThe paper deals with a comparison between different multiobjective optimisation algorithms, namely Adaptive Pareto Algorithm (APA), Genetic Algorithm (GA) and Parameter Space Investigation (PSI). The comparison has been completed by solving a test problem (ZDT1) widely considered in the literature and a real engineering problem concerning the optimisation of traction electric motors. The practical problem is addressed with the help of a specific custom-made tool for the optimisation of electric motors, where Motor-CADTMis used as multi-physics simulation software. Several metrics have been defined to objectively characterize the Pareto-optimal solutions obtained with the different algorithms
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Comparison of different electromagnetic forces calculation methods for the analysis of NVH behaviour of electric motors
No full textThis paper deals with NVH (Noise Vibration and Harshness) analysis of electric motors for automotive applications. A comparison between numerical and analytical magnetic force computation methods is conducted. Altair Flux, Ansys Maxwell and Ansys Motor-CAD are the commercial software considered, while the analytical expression of the airgap magnetic field is defined by means of the image method. A 12 pole 18 slot combination Permanent Magnet Synchronous Motor (PMSM) is considered as benchmark machine. In order to evaluate the acoustic emission of the PMSM a 2D circular beam model is considered. The main spatial-temporal components of the calculated radial and tangential harmonic forces are used as input for the NVH analytical model. Differences at the force calculation level are analyzed to investigate how they affect the prediction at the acoustic noise level for the considered electric motor
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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