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Re: Solid state TC working! But.
Subject:
Re: Solid state TC working! But. (fwd)
Date:
Sun, 16 Mar 1997 21:38:43 -0700 (MST)
From:
List owner <listown-at-poodle.pupman-dot-com>
To:
tesla-at-poodle.pupman-dot-com
---------- Forwarded message ----------
Date: Fri, 14 Mar 1997 12:30:41 -0700
From: Harri Suomalainen <haba-at-cc.hut.fi>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Solid state TC working! But.
Some SMPS topologies do indeed use gapping. Flyback topology needs
a gapped core for increased energy storage capability in the same
core. It can be shown that energy is mostly stored in the gap in
that case. Non-gapped cores would be a lot bigger for same power
output (energy storage capability).
Topologies like forward and some others use gapping to dilute
unwanted effects in the core. Usually they want to smear the B-H
loop so some gapping is used.
Then there is the 3rd case: preventing saturation etc. Sometimes
it may be desirable to make the core able to take some amount of
dc component without saturation. Often topologies take very
good means like series capasitors in the primary side to keep
any dc away from the transformer. If that is not feasible gapping
may help. Gapping may also help in transient conditions like at
the startup.
Most often topologies like half bridge use current detecting and
limiting to be able to handle eg. transients and any problems.
Series caps are used to keep dc away from the transformer.
Then they are surely able to use ungapped cores. Having core
not gapped will keep the effective permeability high (gapping
would lower it a lot). That will mean higher magnetizing inductance
and an improved power factor compared to a gapped core.
Hope this short description will help fellow solid-stace coilers
understand transformers better.
--
We have phone numbers already, why would we need IP-numbers! -unknown
person
Harri.Suomalainen-at-hut.fi - PGP key available by fingering
haba-at-alpha.hut.fi