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William Murray

Designing Magnetics

William Murray
SunitaT0
SunitaT0
7/30/2013 11:55:25 PM
User Rank
Master
Re : Designing Magnetics
The requirement of optimal magnetics design is loss minimization. The magnetics components are most costly as they are not properly designed. If removal heat from the device is possible, lower losses will always advantage the design.

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Brad Albing
Brad Albing
7/6/2013 1:32:37 PM
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Blogger
Re: Core material
Ah - so this is for a down hole drilling application then. From my previous experience, those apps are some of the most stringent.

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William Murray
William Murray
7/6/2013 11:12:02 AM
User Rank
Blogger
Re: Core material
All -- I used Laminated Iron Core, because Ferrite would disintigrate and lose it's properties at 300 deg F. (Design operating temperature for the PWM filter inductor)

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DaeJ
DaeJ
7/6/2013 10:31:23 AM
User Rank
Master
Design of experiment - Magnetic
Simulation design provides the good guideline at the initial stage. I am wondering how the simulation model is fitted into high nonlinear hystersis as the polarity of particles is changing. I guess that there is some comparsion between actual data and simulated data in the magnetic system.

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D Feucht
D Feucht
7/5/2013 10:19:40 PM
User Rank
Blogger
Re: Core material
William,

The Caltech guys in CO put much emphasis on equating magnetic (core) and electrical (winding) losses because, according to the max power-xfr theorem, this transfers the most power. However, this is a broad optimum and for linear magnetics is at equal power loss in each. (Erickson & Macsimovic's book also work out the optimal values for nonlinear magnetics but the optimum is broad and if the magnetics becomes too nonlinear, there are other bigger problems.)

However, nobody seems to have realized that to maximize magnetic (core) utilization and hence minimize core size is to operate the core, within acceptable design margins, near both saturation and max power loss. These are the conditions under which you can achieve the maximum power transfer from a core, and it depends on waveform parameters. I have worked all this out in detail at

http://www.how2power.com/newsletters/1102/articles/H2PToday1102_design_Innovatia.pdf

and it might be of interest in your efforts at magnetics design optimization. Also, see

http://www.how2power.com/newsletters/1103/articles/H2PToday1103_design_Innovatia.pdf

for a different look at the same optimization.

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eafpres1
eafpres1
7/5/2013 1:25:45 PM
User Rank
Blogger
Core material
Hi William--I'm guessing in your application the core was a metallic core material?  There are also a lot of wound inductors made on ferrite toroid cores.  A problem would be getting good properties and whether the simulation tool accurately accounts for the behavior of the core.  Can you expand a bit on what core you used and if it was easy to get the properties for the simulation?

In a comapny I worked for previously (Laird) they make a broad line of soft ferrite products, including bare cores (toroids).  I believe they provide Spice models for all of them.  I'm not sure how broadly standard that practice is in the magentics industry.  What has your experience been there?

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