PMSM Design and Loss Analysis Liping Zheng 07/23/2003

PMSM Configuration Litz-wire: 1.78 mm x 2.27 mm 50 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 in (0.025 mm) tolerance.  According to new PM profile, adjust the winding configuration and perform all simulations.  Filter inductor preliminary design.

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.

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 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 Filters  Copper Loss (3 turns):  1.2W  Core loss (3C91):  50mW/cm 10KHz (from manufacturer’s data).  Estimated 10mW /cm 3.3KHz.  Estimated 20mW /cm 3 considering harmonics.  The volume is 124 cm 3  2.48W  Total loss of the filters (3 inductors):  3x ( )=11W.

PMSM Loss Copper loss16.9 W Shaft eddy loss0 ? Iron loss10.4 W Bearing loss10 W Filters loss11 W Windage loss12.8 W Total loss61.1W Motor Efficiency: Control Efficiency: Total Efficiency: Future work