PMSM Design

Liping Zheng

03/28/03

Winding Configuration

Round Wire Rectangular Wire

Four Possible Winding Configuration

AWG14 AWG13 Litz

rectangle

Litz

round

Dshaft(mm) 14 15.5 16 18

Dwire(mm) 1.71 1.913 1.78x2.27 2.21

R1(mm) 8.43 9.28 8.5 10.68

R2(mm) 9.89 10.9 10.83 12.64

Di(mm) 21.64 23.9 25.5 27.65

Do(mm) 34 36 38 40

Length(mm) 25.4 25.4 25.4 25.4

Wire SelectionSolid copper wire

AWG13(Do:75mil, R:2mΩ/ft)AWG14(Do:67mil,R:2.6mΩ/ft)

Litz wire(multi-strand configuration)RoundLitz WireRectangular

Benefit of using Litz-wireEasy shape.Reduce skin effect, proximity effect.Each strand tends to take all possible positions in the

cross-section of the entire conductor.

Airgap Flux and Leakage

Back EMF Difference Due to Leakage

Back EMF difference may cause big problem in Solid wire.

Rectangular Litz Wire Configuration

Dshaft 16mm

Lgap 0.5mm

R1 8.5mm

R2 10.83mm

Di 25.4mm

Do 36mm

a 1.78mm

b 2.27mm

Length of Stator: 25.4mm

Simulated Back EMF-Litz Rectangular Wire Configuration

Simulated Current-Litz Rectangular Wire Configuration

Simulation results for different PM Width(W)

Flux lines for different PM Width

W=6mm W=8mm W=10mm

W=12mm W=all

Shaft Structure

Further Work

Order the rectangular Litz-wire in advance.Optimize PM structure.Design Shaft structure.

Full stress analysis.