Coupl5: Saturable reactor

The AC reactor features a magnetic core that can be deliberately saturated by means of a direct electric current in a control winding. Calculate the reactor inductance for a set of operating currents.

Problem Type:
A plane-parallel problem of nonlinear DC magnetics coupled to AC magnetics.

Geometry:

Given:
Magnetic permeability of the steel core μ - nonlinear, shown on the plot below;
AC winding current value I~ = 300 A;
AC winding number of turns n = 300;
Frequency f = 50 Hz;
Control DC current density j_ = 0.. 2 A/mm2;

Problem:
Calculate the reactor inductance for a set of operating currents.

Solution:
DC magnetic field is calculated with DC Magnetics module of QuickField. AC magnetic field is calculated with AC Magnetics module of QuickField. In order to take saturation into account the link from DC to AC is added. The link transfers the steel core magnetic permeability distribution from one problem to another.
Series of problems were calculated for a number of control currents.

Results:

Control DC current
j_, A/mm2
Inductance on AC current
L~, H 
0 0.54
1 0.29
2 0.17

See the Coupl5MS.pbm, Coupl5HE.pbm problems in the Examples folder.