Overview
Closeup |
Motors used in electric power steering are constructed by using a divided
stator core to miniaturize the motor and generate higher output. The press-fitting
stress needs to be accounted for in the iron loss analysis because the
stress caused by press-fitting is known to increase the iron losses when
magnetic steel sheets are used for a divided stator core that has a frame
with press fitting.
This note presents the use of a structural analysis and magnetic field
analysis to obtain the iron loss density of a IPM motor that has no-load
with and without the stress by simulating the stress caused by the press
fit core and frame with the press fit condition. |
Minimum Principal Stress Distribution
The minimum principal stress distribution is indicated in Fig. 1. Tensile
stress occurs in the frame and teeth, but compressive stress that especially
affects the iron losses is produced largely in the divided core. The compressive
stress is especially large in the area of the model within the square in
Fig. 1, but this is because of the slots' geometry.
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Closeup |
Iron Loss Density Distribution
Closeup |
The iron loss density distribution is indicated in Fig. 2. The iron loss
density distribution increases 9% depending on whether or not the stress
is applied. An analysis that accounts for the compressive stress caused
by the press-fitting needs to be performed to evaluate the iron losses
more accurately because the iron losses increase when the compressive stress
is applied. |
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