[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

# Re: [femm] inductance calculations in nonlinear material

- To: femm@yahoogroups.com
- Subject: Re: [femm] inductance calculations in nonlinear material
- From: Keith Gregory <k.gregory@lboro.ac.uk>
- Date: Thu, 12 Jul 2001 08:29:31 +0100
- In-reply-to: <12160.994851243@www58.gmx.net>

`Cornelius,`
`At 13:34 11/07/01 +0200, you wrote:`

>     Anyway, as far as I understand it, the direct calculation of mutual
>     inductance
>     can only be done via the flux linkage approach.

`
You are probably right in the non-linear case but in a linear situation there is a simple way of getting mutual inductance from the individual self inductances and the self inductance of two windings connected in series, either adding or opposing it doesn't really matter. This only works in linear systems though because it changes saturation levels in non-linear systems.`

>     Flux linkage must be determined from the magnetic vector potential
>     difference
>     which is an order less accurate than energy computed from variational FEM.

> `Therefore I expect some differences in the results per se.`

>     >It should be possible as well to model the transformer in the section at
>     >right angles to the normal one to get some idea of the end-winding leakage.
>     >Because the leakage is mostly in air superposition theory should apply
>     >reasonably well and you may be able to just add the leakage fluxes
>     >together. You need to be aware though that the core material will be at a
>     >different level of saturation in the "end-winding" model although you
>     >could make the core material linear and set its permeability to a typical
>     >value from the "normal" model.
>     >
>     >Remember as well that with ferromagnetic or ferrimagnetic core materials
>     >the inductances will be functions of current because of saturation,
>     >although this may not affect the leakage too much.

>     As I see it the affect of nonlinear core material on leakage inductance
>     can merely be neglected,
>     at least at the level of accuracy I need here.

`
Probably true.`

>     Computing the proper values for self inductances when nonlinear core
>     material
>     is present is another chapter though!
>     Up to now I have only used linear material,
>     I have not yet fully understood how to interpret the different "inductance"
>     values that can be computed from energy / coenergy / apparent energy ...

`
You need to get a grasp of what inductance is and then the understanding comes a little easier. It's really just a "fiddle factor" to describe in analytic terms the effects of induced emf produced by a changing magnetic field.`

>     regards,
>     Cornelius

>     --
>     GMX - Die Kommunikationsplattform im Internet.
>     http://www.gmx.net

> `GMX Tipp:`

>     Machen Sie Ihr Hobby zu Geld bei unserem Partner 1&1!
>     http://profiseller.de/info/index.php3?ac=OM.PS.PS003K00596T0409a

> ``
> `
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/`

    Keith Gregory
    Department of Electronic & Electrical Engineering
    Loughborough University
    Phone: 01509 227025 Fax: 01509 227014
    Department web: http://www.lboro.ac.uk/departments/el/

- References:
  - inductance calculations in nonlinear material
    - From: corneliuspaul@gmx.de

- Prev by Date: inductance calculations in nonlinear material
- Next by Date: Re: Crosstalk mode? / --> transformer calculation summary
- Previous by thread: inductance calculations in nonlinear material
- Next by thread: Re: Crosstalk mode? / --> transformer calculation summary
- Index(es):
  - Date
  - Thread