an efficient method for analysis and design of permanent magnet machines - presentation_hung...

7/24/2019 An Efficient Method for Analysis and Design of Permanent Magnet Machines - Presentation_Hung Vu_IEEE-YRS_ 17April2012

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An Efficient Method for Anal sis and

Design of Permanent Magnet Machinewith Concentrated Windin s

Special Attention to Slotting Effect

Hung Vu Xuan

11

EPPElectrical Power Processing


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Outlines

1. Efficient method for analysis and design

. o ng e ec on s r u on o ux ens y n a r gap

3. Slotting effect on flux density in magnets

.

5. Slotting effect on torque

.

7. Experimental validation

.

Electrical Power Processing


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1. Efficient method for analysis and design: Automated nonlinear transient 2D-FEM including

rotor motion with abilities:

Automated geometry by script

Automated handle boundary conditions andcomputation by script

Program developed as described in flowchart

Platform: Comsol coupling to Matlab

Design optimization requires many iterations

Advantages: flexibility, save time

Flowchart for

design.



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2D vs. 3D simulation:

, computer and very time-consuming!!!



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Video 2D-transient FEM simulation:

Flux contour Surface flux density



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2. Slotting effect on distribution of

magne c e n a r gap

Slotting effect: distortwaveform, reducingmean flux densit 0.4

0.6

.

rgap(T) Semi-open slot

Fully open slot

Closed slot

Closed-slot

Results: Coggingtorque, torque ripple,

0

0.2

ensityinai

Semi-open slot

Fully open slot

vo age r pp e,

-0.6

-0.4

- .

Radialflu

x

o open ng

0 5 10 15 20 25 30 35 40-0.8

Mechanical angle (degree)

Fig: Radial flux density in the middle of the air gap for cases:

full-open slot, semi-open slot and closed slot.



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3. Slotting effect on distribution of magnetic field

0.8

1 Fully open slot

Semi-open slotMa net ed e

Slotting effect

0.4

0.6

agnetsBr(T) effect

Leakage flux Causing eddy -0.2

0

.

xdensityin

Slotting effect

.

-0.8

-0.6

-0.4

Radialfl

Leakage flux density inthe air between

0 5 10 15 20 25 30 35 40-1

Mechanical angle (degree)

Fig: Distribution of radial flux density in magnets.



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4. Slotting effect on voltage and flux linkage

Slotting effect at small slot opening:

Fig: Voltage vs. slot opening At small slot Fig : Flux linkage vs. slot opening



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Leakage flux passing through tooth tip

of closed slot PM machine.



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5. Slotting effect on torque

Fig: Mean torque vs. slot opening

Optimal slot opening for maximizing

mean torque and minimizing torque

Fig: Torque ripple vs. slot opening



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6. Slotting effect on iron losses2.5

x 106

Semi-open slot

0.5

1

1.5

2

nmagnets(A/m

m2

)Fully open slot

Fig : Eddy current density at a point in magnet

-1.5

-1

-0.5

0

Eddy

currentdensityi vs. s o open ng.

Amplitude of eddy current at a point in

magnet depends on slot opening.

0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

x 10-3

-2.5

-2

Time (sec)

depend on slot opening.

Fig: Voltage and eddy current loss vs. slot

.

Choosing slot opening for maximizing

voltage and minimizing eddy current.



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Slotting effect on losses:

Fig: influence of slot opening on ,

loss and total iron loss.

loss is increasing, when slotopening increases.

Stator iron loss is decreasin

when slot opening is higher than4 mm



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7. Experimental validation

Outer rotor PM machines

with concentrated windings

in a flywheel for validation

Stator with semi-open slot Stator with fully open slot



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Flux linkage and internal voltage:

0.6

atooth(mWb)

Experiement (Volt)

Simulation (Volt)

Experiment (mWb)

Simulation mWb

0.2

0.4

age

fluxthrough

Internal voltage

-0.2

0

rn(V),andLink

-0.6

-0.4

alvoltageofat ux n age

0.5 1 1.5 2 2.5 3 3.5-0.8

Inter

Time (ms)

flux linkage and internal voltage of semi-open slot machine.



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Experimental validation of slotting effect on internal voltage:

a

Fig: Internal voltage vs. rotor speed, a) semi-open slot, b) fully open slot.



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8. Conclusions

Proposed concept in form of flowchart for analysis and design of PM.

Gave insi ht into the influence of slottin on erformances of PMmachine at small slot opening.

p m za on o s o open ng or max m z ng vo age, mean orquemeanwhile minimizing total loss.

Experimental validation of the influence of slotting on flux linkage and

voltage./.



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Thanks for your attention!

Questions?


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