PMSM Design and Loss Analysis

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PMSM Design and Loss Analysis

• Liping Zheng
• 07/23/2003

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PMSM Configuration
Litz-wire 1.78 mm x 2.27 mm 50
strands _at_ AWG 30 Gap 0.5 mm Stator Di 25.5
mm Do 38 mm Length 25.4
mm Shaft diameter 16 mm
No major shaft stress problem if we select high
stress shaft material.
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Progress

• Got the Litz-wire with rectangular profile.
• Total 22 lb.
• Found the permanent magnets (PM) manufacturer to
  fabricate the special shape PM with 0.001 in
  (0.025 mm) tolerance.

• According to new PM profile, adjust the winding
  configuration and perform all simulations.
• Filter inductor preliminary design.

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Shaft Cross Section
Shaft Cross-section
Ø 16
5
2.5
2.5
5
(mm)
Courtesy of Dipjyoti Acharya
All Dimensions are in mm
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Airgap Flux Density

• Low harmonics of the normal flux density.
• Tangent flux density is a little large due to
  large airgap.

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Simulated Torque
1.5 ripple

• Winding pitch is modified from 12/15 to 10/15.
• Simulated back EMF12 V
• Use Generator mode to simulate Torque.
• Load current 60.8 A

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Inductor Design
Constraints
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DC Filter Inductor

• Negligible core loss, proximity loss.
• Copper loss dominated.
• Flux density chosen simply to avoid saturation.
• Airgap is employed.

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AC Filter Inductor

• Core loss, copper loss, proximity loss are all
  significant.
• Flux density is chosen to reduce core loss.
• A high-frequency core must be employed.
• An air gap is employed.

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P Core Structure-p66/56
d166.29 mm d254.51 mm d328.19
mm h157.3 h243.28
Ferrite type MnZn (manganese and zinc) Material
3C81,3C91
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Use P66/56 core
Copper loss 1.2W
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Loss of Filters

• Copper Loss (3 turns)
• 1.2W
• Core loss (3C91)
• 50mW/cm3 _at_ 10KHz (from manufacturers data).
• Estimated 10mW /cm3 _at_ 3.3KHz.
• Estimated 20mW /cm3 considering harmonics.
• The volume is 124 cm3 ?2.48W
• Total loss of the filters (3 inductors)
• 3x (1.22.48)11W.

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PMSM Loss
Copper loss 16.9 W
Shaft eddy loss 0 ?
Iron loss 10.4 W
Bearing loss 10 W
Filters loss 11 W
Windage loss 12.8 W
Total loss 61.1W
Future work
Motor Efficiency
Control Efficiency
Total Efficiency