Comparison of analytical and Finite Element calculation of eddy-current losses in PM machines

Jassal, A.; Polinder, H.; Lahaye, Domenico; Ferreira, J.A.

doi:10.1109/icelmach.2010.5607907

Cited by 11 publications

(6 citation statements)

References 8 publications

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“…The computation of hysteresis losses in permanent magnets is very complex and still represents an open issue. Although hysteresis losses in magnets prevail over eddy-current losses at high frequencies [40], their influence below several hundred Hz is generally neglected [41]- [43]. As the analysis of hysteresis losses in magnets is beyond the scope of this paper, they will be neglected.…”

Section: Rotor Eddy Currentsmentioning

confidence: 97%

Electromagnetic Analysis of Axial-Flux Permanent Magnet Synchronous Machines With Fractional Windings With Experimental Validation

Stefano

Marignetti

2012

IEEE Trans. Ind. Electron.

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Axial-flux permanent magnet (PM) synchronous machines are suitable for direct drive applications. Axial-flux PM synchronous machines with fractional windings provide high power density, low torque ripple, and sinusoidal phase voltages, but suffer from high rotor losses due to stator field harmonics and slotting. This paper formulates an electromagnetic model based on the polar coordinate representation of the air-gap magnetic field. No-load and load tests are carried out on a soft-magneticcomposite stator axial-flux machine to validate the model. Rotor losses represent the largest loss figure in this machine. Most rotor losses are due to slotting harmonics.

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Section: Rotor Eddy Currentsmentioning

confidence: 97%

Electromagnetic Analysis of Axial-Flux Permanent Magnet Synchronous Machines With Fractional Windings With Experimental Validation

Stefano

Marignetti

2012

IEEE Trans. Ind. Electron.

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“…Deak et al [11] suggest to eliminate the average valueJ e from the calculated current density. Then, just the alternating current density value J e remains J e = J e −J e (8) whereJ e corresponds to Finally, the eddy-current losses could be calculated as follows:…”

Section: B Radial 2-d Fe Simulation With Eddy Currentsmentioning

confidence: 99%

Permanent Magnet Eddy-Current Losses in 2-D FEM Simulations of Electrical Machines

2015

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The prediction and calculation of eddy current losses occurring in permanent magnets (PMs) of electrical machines is of great interest. Most accurate results are achieved using 3-D finite-element (FE) simulations, which require long computation times and elaborate models. Due to this, 3-D methods are only applied in the final stage of the machine design process. This paper presents different methods to calculate eddy-current losses in PMs by 2-D FE simulations. A radial 2-D FE solver in combination with an axial 2-D FE solver is developed enabling the prediction of the eddy current paths in three dimensions with the associated losses. This approach is applicable to both surface mounted and interior PMs.

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“…Therefore, several empirical calculation methods are developed and compared in [28] and [29]. However, we implemented the numerical method of Ede [9], which couples a 2D FEM and a 3D FEM: from the static 2D FEM of the complete machine, which is run for several rotor positions, the magnetic flux density vector is recorded in a grid of points in the magnet, as a function of time (or rotor position).…”

Section: E Magnet Loss Caused By Space Harmonicsmentioning

confidence: 99%

Influence of the Amount of Permanent-Magnet Material in Fractional-Slot Permanent-Magnet Synchronous Machines

Sergeant

Bossche

2014

IEEE Trans. Ind. Electron.

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Abstract-The efficiency of permanent magnet synchronous machines (PMSM) with outer rotor and concentrated windings is investigated as a function of the mass of magnets used, keeping the power, volume and mechanical air gap thickness constant. In order to be useful for electric vehicle motors and wind turbine generators, the efficiency is computed in a wide speed and torque range, including overload. For a given type and amount of magnets, the geometry of the machine and the efficiency map are computed by analytical models and finite element models, taken into account iron loss, copper loss, magnet loss and pulse width modulation loss. The models are validated by experiments. Furthermore, the demagnetization risk and torque ripple are studied as a function of the mass of magnets in the machine. The effect of the mass of magnets is investigated for several soft magnetic materials, several combinations of number of poles and number of stator slots, and for both rare earth (NdFeB) magnets and ferrite magnets. It is observed that the amount of permanent magnet material can vary in a wide range with a minor influence on the efficiency, torque density, and torque ripple and with a limited demagnetization risk. A lot of papers deal with rotor losses in the considered type of machines, and give methods to compute them. For example [6] gives a general method for several slot/pole configurations. Polinder [7] studies losses in the solid back iron of PMSM with fractional slot windings. Atallah presented an analytical model to compute magnet loss [8], and Ede proposed a computationally efficient 3D numerical method to compute the magnet loss [9]. IndexAn aspect of fractional-slot concentrated-winding PMSM's that is less investigated, is how much the amount of magnets can be reduced, and how this affects the global machine design and performance. As the price of rare earth magnets is high, PMSM's with small amount of magnets become interesting, on condition that their efficiency and torque density remain high. It is known that very powerful and light permanent magnet machines can be made when a lot of PM material can be used: for example the slotless brushless DC PMSM of [10] has two concentric rotors, both of them completely covered with a thick layer of NdFeB magnets in Halbach array. Alternatives are investigated to reduce the required amount of permanent magnets, or even to have motors without magnets [11]. Nevertheless, [12] compared caged induction, reluctance, and PM motor technologies for the more electric aircraft, concluding that three-phase permanent magnet machines may still be the favorite choice.Therefore, we investigate the impact of the amount of magnets and the magnetic material grade in the stator of the PMSM on the efficiency, keeping the machine volume and torque density constant. Here, we consider not only the efficiency at nominal speed N nom and torque T nom , but also the average efficiency in the speed range 0.25-1.50×N nom and torque range 0.25-1.50×T nom . A number of effects of reducing the amount ...

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Comparison of analytical and Finite Element calculation of eddy-current losses in PM machines

Cited by 11 publications

References 8 publications

Electromagnetic Analysis of Axial-Flux Permanent Magnet Synchronous Machines With Fractional Windings With Experimental Validation

Electromagnetic Analysis of Axial-Flux Permanent Magnet Synchronous Machines With Fractional Windings With Experimental Validation

Permanent Magnet Eddy-Current Losses in 2-D FEM Simulations of Electrical Machines

Influence of the Amount of Permanent-Magnet Material in Fractional-Slot Permanent-Magnet Synchronous Machines

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