eddy current distribution in rotor of permanent magnet generators using 3d transient fem

8/11/2019 Eddy Current Distribution in Rotor of Permanent Magnet Generators using 3D Transient FEM

1/14

Hung Vu

[email protected]

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Eddy Current Distribution in Rotor ofPermanent Magnet Generators

using 3D Transient FEM

Hung Vu, PhD


2/14

Hung Vu

[email protected]


Outline

Geometry model,

3D transient Finite Element Model (FEM),

Rotor eddy current distribution during noload,

Rotor eddy current distribution due to current-carrying windings, and

Segmentation magnet to reduce eddy current

loss.

conclusion


3/14

Hung Vu

[email protected]


Geometry Model


4/14

Hung Vu

[email protected]


3D Transient FEM Modeling

Hybrid between Scalar Magnetic Potential

and Vector Magnetic Potential

0 0

e

r

m

AH J

t

B A

H

H V

Governing equations of the magnetic field:


5/14

Hung Vu

[email protected]


Magnetic Fields in a Domain without

Currents using Scalar Magnetic Potential Vm

In magnetostatic problems where no electric currents

are present, it is possible to formulate and solve the

problem using a scalar magnetic potential.

In a current-free region: H= 0 (Amprs Law)

This implies that the magnetic scalar potential Vm canbe defined from the relation: H = Vm

Using the constitutive relation: B = 0rH+Br, the

equationB = 0 (Gauss Law) becomes:

0 0r mV rB


6/14

Hung Vu

[email protected]


Magnetic Fields in a Domain with Currents

using Vector Magnetic PotentialA

1 1

0

1 1

0

1 10

( ) , or

( ) , or

( ) ( )

( )

r

r

r

t

t

t

t

r e

r e

r e

e

AB B v B J

AB B v B J

AA B v A J

AJ v A J

where, Je

is an external current density, v is the velocity of

the conductor, is scalar electric potential, and J is total

current.


7/14

Hung Vu

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Meshing

Tetrahedral meshes


8/14

Hung Vu

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Rotor eddy current distribution during noload


9/14

Hung Vu

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Eddy Current in Rotor Yoke

During noload


10/14

Hung Vu

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Magnet eddy current distribution due to

current-carrying windings alone

External current in windings

Magnet eddy current distribution


11/14

Hung Vu

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Segmented magnets

3 segmentations in the

axial direction.3x3 segmentations.


12/14

Hung Vu

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Reducing Eddy Current by using

Magnet Segmentations

Note: During noload, fully open slot, 3000 rpm.


13/14

Hung Vu

[email protected]


Comparison of 2D and 3D computation

20

125

25

100

0

20

40

60

80

100

120

140

1 3

Magnet segmentation number

Eddycurrentlossesinmagnets(W)

Fully-open slot, 3D

Fully open slot, 2D


14/14

Hung Vu

[email protected]


Video of eddy current

eddy current distribution in rotor of permanent magnet generators using 3d transient fem

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