Iron core loss in transient excitation mode - QuickField simulation example
Core losses in a ferromagnetic core driven by rectangular pulse excitation, including the transient magnetic-flux-density waveform during the cycle.
How to find transient core losses under rectangular pulse excitation?
Answer Typical applications Geometry
Given
Task
Solution 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.
Results
Total core loss is 19 mW.
References:
Engineering question
Use transient magnetics to obtain the core flux-density waveform, then evaluate the loss density with the rectangular-wave Steinmetz-type equation for the core material.
transformer magnetic cores, pulsed magnetic cores, rectangular excitation cores
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Simulation problem
Problem Type
Plane-parallel problem of transient magnetics.
Core type: E19/8/5-3C81 [1]
Magnetic permeability of MnZn ferrite μ=2700
Primary winding:
Number of turns - 80
Waveform - periodic rectangular wave
Frequency - 20 kHz
Voltage magnitude - 40 V
Calculate core loss.
According to [2] 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.
This may be easily implemented using Microsoft Excel and QuickField.
Magnetic flux density distribution at t = 2.5 ms (maximal values).
[1] Ferroxcube E19/8/5, E cores and accessories
[2] 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.
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