PMSM Design and Loss Analysis

Liping Zheng

07/23/2003

PMSM Configuration

Litz-wire:

1.78 mm x 2.27 mm

50 strands @ 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.

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.

5

5

2.5

2.5

Ø 16

All Dimensions are in mm

Shaft Cross-section

Shaft Cross Section

Courtesy of Dipjyoti Acharya

(mm)

Airgap Flux Density

Low harmonics of the normal flux density.

Tangent flux density is a little large due to large airgap.

0.0000 0.0001 0.0002 0.0003 0.0004-0.12

-0.10

-0.08

-0.06

-0.04

-0.02

0.00T

orq

ue (

N.m

)

Time (s)

Simulated Torque

Winding pitch is modified from 12/15 to 10/15.

Simulated back EMF=12 V

Use Generator mode to simulate Torque.

Load current = 60.8 A

1.5% ripple

Inductor Design

W

T

WAu

ggc

g

c

g

g

A

nlR

nAWK

lBRABnI

l

nA

R

nL

Rni

0maxmaxmax

20

2

Constraints:

DC Filter Inductor

Negligible core loss, proximity loss.

Copper loss dominated.

Flux density chosen simply to avoid saturation.

Airgap is employed.

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.

P Core Structure-p66/56

d1=66.29 mm

d2=54.51 mm

d3=28.19 mm

h1=57.3

h2=43.28

Ferrite type: MnZn (manganese and zinc)

Material :3C81,3C91

Use P66/56 core

Copper loss

1.2W

Loss of FiltersCopper Loss (3 turns):

1.2W

Core loss (3C91):

50mW/cm3 @ 10KHz (from manufacturer’s data).

Estimated 10mW /cm3 @ 3.3KHz.

Estimated 20mW /cm3 considering harmonics.

The volume is 124 cm3 2.48W

Total loss of the filters (3 inductors):

3x (1.2+2.48)=11W.

PMSM LossCopper 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

%97)1.612000(2000 m

%95c%1.92 mc

Motor Efficiency:

Control Efficiency:

Total Efficiency:

Future work