Magn5: Armature Winding Inductance

This example demonstrates how to calculate the inductance of a single stator phase coil in a permanent magnet synchronous motor.

Analysis Type:

Plane-parallel nonlinear magnetostatic analysis with media magnetic state remembering capability.

Geometry model:

Three-phase permanent magnet synchronous motor

The length of the motor in the axial direction is 200 mm.

Parameters:

The magnet coercive force Hc = 500 kA/m;
The magnet remanence Br = 0.63 T;
The rated current density in the stator coil j = 2 A/mm2;
The core permeability μ is given by the B-H curve.

Solution:

We calculate the phase coil inductance for the normal operating point dividing the magnetic flux through the coil by the current density that generates the flux.
With QuickField, you would normally turn off permanent magnets' magnetization and the current in all phase coils but one. In our case, however, this would cause significant deviation in core saturation from the normal operating point. Which, in turn, would make the calculated inductance value inexact.

To avoid that, we are splitting the problem into two parts:

The 2nd part of the problem keeps all sources except the A-phase switched off. We calculate the inductance as the magnetic flux divided by the current with the help of Inductance Wizard.

Results:

Plot of relative permeability

Current, dI

31.2 A

Flux linkage,

37 μWb

Phase inductance, dL

1.2 μH


See Magn5_base.pbm and Magn5_a.pbm problems in the Examples folder.