Magn4: Electric motor

A brushless DC motor with permanent magnets and three phase coil excitation.

Problem Type:
A nonlinear plane-parallel problem of magnetostatics.

Geometry:
Three-phase permanent magnet synchronous motor Calculate the inductance of a single stator phase coil in a permanent magnet synchronous motor Cobalt alloy Steel N S N S A A A A B B B B C C C C Ø50 Ø10 40

Axial length of the motor is 40 mm.

Given:

The four magnets are made of Samarium-Cobalt with relative permeability of 1.154 and coercive force of 550000 A/m. The currents for each phase coil are as follows: 13.5 A on R+, –13.5 A on R, 13.5 A on S+, –13.5 A on S, and zero on T+ and T. The inner and outer frames are made of Cobalt-Nickel-Copper-Iron alloy.

The B-H curve for the Cobalt-Nickel-Copper-Iron alloy:

H (A/m) 20 60 80 95 105 120
B (T) 0.19 0.65 0.87 1.04 1.18 1.24
H (A/m) 140 160 180 200 240 2500
B (T) 1.272 1.3 1.32 1.34 1.36 1.45

The B-H curve for the steel:

H (A/m) 400 600 800 1000 1400 2000 3000 4000 6000
B (T) 0.73 0.92 1.05 1.15 1.28 1.42 1.52 1.58 1.60

See the Magn4.pbm problem in the Examples folder.