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Calculation methods for eddy current losses with the example of a permanent magnet excited synchronous machine inside the threshing cylinder of a combine harvester

Schuffenhauer U., Michalke N.

Czasopismo Techniczne. Elektrotechnika

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2015

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Y. 112, iss. 1-E

241--250

EN

Electrical drives become more and more interesting for many applications in mobile machines including farming equipment. In this paper, the electromagnetic design of a threshing cylin der for an electrical combine harvester with a function-fitted external rotor and an inner stator is shown. Special attention will be paid to the calculation of the eddy current losses within the magnets through different FEM methods. The influence on the losses of segmentation of magnets in tangential and axial directions is shown.

PL

Napędy elektryczne stają się coraz bardziej atrakcyjne również w aplikacjach maszyn ruchomych, włączając w to również maszyny rolnicze. W niniejszym artykule omówiona została konstrukcja młockarni dla elektrycznego kombajnu zbożowego z zewnętrznym wirnikiem i wewnętrznym stojanem. Szczególną uwagę zwrócono na obliczenia strat prądów wirowych w obrębie magnesów z użyciem obliczeń MES. Pokazany został wpływ segmentacji magnesów w kierunku stycznym oraz osiowym na straty.

2

Calculation methods for eddy current losses at the example of a permanent excited synchronous machine inside the threshing cylinder of a combine harvester

Schuffenhauer U., Michalke N.

Maszyny Elektryczne : zeszyty problemowe

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2014

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Nr 4(104)

61--66

EN

New electrical drive concepts make it possible to put a high functionality into a restricted structural form. Therefore electrical drives become more and more interesting also for applications in mobile working machines including the farming ones. In this paper is shown the electromagnetic design of a threshing cylinder for an electrical combine harvester with function-fitted external rotor and an inner stator using tooth Winding technology. Special attention will be paid on the calculation of the eddy current losses within the magnets by different software solutions. Firstly is presented the combination of 2D-FEM methods with analytical computations using the analysis of the transient field course by discrete Fourier analysis. These are compared with calculation of the eddy currents and losses with a real dynamic field calculation by means of 3D-FEM. The calculated losses are summed up for all elements and are summarized in loss zones respectively. It is shown the influence of the segmentation of the magnets in tangential and axial direction on the losses as well as it is established the connection to the analytical procedure.

3

Cooling of electric machines by multi-phase systems

Schuffenhauer U., Urbański W., Michalke N., Kuß H.

Maszyny Elektryczne : zeszyty problemowe

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2010

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Nr 88

97-102

EN

A high potential for increase the power density and the efficiency of electrical machines consists in a improved cooling. A new implementation approach is in the pouring of the electric components into a medium, which guarantees a better heat emission to the case in a combined manner with a new cooling concept by utilization of change its phase, with that maximum loads can be absorbed thermally. At a realistic experimental model on the basis of a 3 kW induction motor of assembly line production the use of the different physical effects during heat storage was examined for the suitability for an electrical machine, when this equipped with chambers with technical paraffin were. There are represented the experimental investigations at a modified induction motor and with its result the potential of this development. Measurement and computations show the better cooling of the solid one and both the liquefied material compared to air circulation. On the other hand, the effect of the fusion heat is still insufficient because of bad heat conduction qualities of PCM material for the practical application. By means of thermal FEM simulations the experiments are supported and possibilities for new materials examined.

4

Radial partitioned reluctance machine as gear pump - an approximation among electrical and fluid power

Schuffenhauer U., Kub H., Michalke N., Wustmann W., Helduser S.

Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej. Studia i Materiały

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2008

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Vol. 62, nr 28

30-39

EN

New operations often demand not only a further development of available technology with the target of increasing the efficiency but also in some case rethinking and breaking through of traditional structures are necessary, which were developed over the course of the technical development. The goal consists in adapting known active principles so, that they are suited for the technological process. The contribution describes the way to the arrangement of an electrical-hydrostatic gear pump of so far unrivaled integration degree. Originating in the particular physical connections common design guidelines are derived. From these criterions and limits for an integrated arrangement are derived. Furthermore fundamental problems arised from the integration are discussed like the consequences of the partition of the motor, the use of a common tooth form and the working out of a material with sufficient properties for both hands.

PL

Najwyższy stopień integracji w technice może być osiągnięty poprzez użycie elementów spełniających wspólne funkcje. W omawianym przykładzie dotyczy to wspólnego użycia zębów pompy zębatkowej i zębów silnika reluktancyjnego. W artykule tym opisany jest sposób projektowania pompy elektryczno-hydraulicznej z nieosiągniętym do tej pory stopniem integracji. Omówione zostały podstawowe problemy, do których należą m.in. projektowanie wymiarów pompy, użycie wspólnego kształtu zęba, dobór odpowiednich materiałów i konsekwencje podziału silnika. W artykule opisany został również prototyp pompy zębatkowej o mocy 1,1 kW, który znajduje zastosowanie w aplikacjach niskociśnieniowych. Ponadto, omówione zostały zalety i granice integracji funkcjonalnej napędu elektrycznego i pompy.

5

Additional losses by magnetic field harmonics in the rotor bars of asynchronous machines and their influence

Schuffenhauer U., Kuß H.

Electrical Power Quality and Utilisation. Journal

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2006

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Vol. 12, nr 2

117-120

EN

Optimizing the efficiency of modern asynchronous machines requires the knowledge of the particular loss components. In this contribution a method shall be presented, where by the transient FEM-calculation the copper losses in the rotor bars by harmonic field effects and the consequential originating harmonic currents can be estimated. By this way the determination of the current density of the rotor current harmonics is carried out along the height of the rotor bar. The loss distribution from the bar bottom to the bar tip is derived from the effective current density and its spatial distribution. The calculation shows, that the additional losses represent a considerable quantum of the total losses, they are partly in the range of the fundamental copper losses and therewith they have a lasting effect on the efficiency of the machine. By convenient geometrical actions a reduction of the additional losses is possible.

6

Determination of the iron losses and rotor additional losses in electric machines by advanced methods

Schuffenhauer U., Kuß H.

Prace Instytutu Elektrotechniki

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2005

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Z. 223

91-112

EN

New demands of modern electric drives cause ever new machine designs. Simultaneous the utilization is increasing. This induces, that usual algorithms for the loss calculation are not valid any more in the full extent. The construction of prototypes should be dispensed with, so accurate calculation methods are necessary. In this contribution methods are presented for calculation of the iron losses of electrical machines. In addition to the short consideration of conventional analytical methods new procedures are regarded, with which both the losses through harmonics and the losses in the rotor and inactive parts of the magnetic circuit can be computed by utilization of the results of static or transient FEM computations.

PL

Nowe wymagania stawiane napędom elektrycznym powodują, że zachodzi potrzeba wykonywania nowych projektów. Jednocześnie zwiększa się stosowanie procesów symulacyjnych. To sprawia, że zwykłe algorytmy obliczające straty nie są wystarczające. Względy oszczędnościowe powodują, że wskazane jest obywanie się bez konstrukcji prototypów dlatego też dokładne metody obliczeń są konieczne. W artykule przedstawiono metody obliczające straty w rdzeniu maszyn elektrycznych. Dodatkowo wzięto pod uwagę klasyczne metody analityczne oraz nowe procedury, w których straty od harmonicznych i straty w wirniku oraz w elementach nieaktywnych obwodu magnetycznego mogą być obliczane przy zastosowaniu metody elementów skończonych.