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Iron core loss in transient excitation mode

QuickField simulation example

This is an example of the iron losses calculation in transient magnetic simulation performed with QuickField software.

Problem Type
Plane problem of transient magnetics.

Geometry
All dimensions are in millimeters
Iron core model

Given
Core type: E19/8/5-3C81 (by Ferroxcube)
Magnetic permeability of MnZn ferrite μ=2700
Primary winding:
    Number of turns - 80
    Waveform - periodic rectangular wave
    Frequency - 20 kHz
    Voltage magnitude - 40 V

Task
Calculate core loss.

Solution
According to Dartmouth university report1 published by Dr. Sullivan and Dr. Harris for rectangular waves it is possible to use Steinmetz-like equation (referred as equation (8) in this report):
Pv[W/m³] = max(k1·fα1·Bβ1, k2·fα2·Bβ2),
with material-dependent parameters, which for the E-core E19/8/5-3C81 from Ferroxcube are:
k1 = 18.02, α1 = 1.23, β1 = 2.45
k2 = 0.000350, α2 = 2.10, β2 = 2.33.

Following this approach, to estimate the losses at a square wave excitation, we need to run Transient Magnetic analysis with a square wave source, and at the moment when the fluxes are at their maximums integrate the volume losses across the parts of our interest.
This may be easily implemented using Microsoft Excel and QuickField.

Results
Magnetic flux density distribution at t = 2.5 ms (maximal values).
core loss rectangular wave

Total core loss is 19 mW.
core loss square wave

*Reference: 1 Testing Core Loss for Rectangular Waveforms, Phase II Final Report, 21 September 2011 by Charles R. Sullivan and John H.Harris; Thayer School of Engineering at Dartmouth.