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ferrite core transformer

M

mukesh

Jan 1, 1970
0
hi sir,

i am working in the UPS field .. i wanted to know that what is the max
freq we can choose for flyback converter ..... i am using the ferrite
core transformer . is there any limitation for freq ? what is the
max working freq for ferrite core transformer??????????
 
M

MooseFET

Jan 1, 1970
0
hi sir,

i am working in the UPS field .. i wanted to know that what is the max
freq we can choose for flyback converter ..... i am using the ferrite
core transformer . is there any limitation for freq ? what is the
max working freq for ferrite core transformer??????????


It depends on the material the core is made from and how much losses
you can stand. Frequencies over 10MHz are often sent through ferrite
materials.

What material eg: 3F3 is the core made from.
 
E

Eeyore

Jan 1, 1970
0
mukesh said:
hi sir,

i am working in the UPS field .. i wanted to know that what is the max
freq we can choose for flyback converter ..... i am using the ferrite
core transformer . is there any limitation for freq ? what is the
max working freq for ferrite core transformer??????????

It depends a lot on the specific material.

There are few sinmple quick answers when it comes to ferrites !

I would suggest though that you download a copy of Epcos's Ferrite Magnetic
Designer application.

Graham
 
D

default

Jan 1, 1970
0
hi sir,

i am working in the UPS field .. i wanted to know that what is the max
freq we can choose for flyback converter ..... i am using the ferrite
core transformer . is there any limitation for freq ? what is the
max working freq for ferrite core transformer??????????

Working in the UPS field? I rather doubt it.

The manufacturers have very specific data on each core material and
what frequency it covers, permeability, hysteresis curves, temperature
range, etc..

Ferrite is a generic description and covers a wide range of materials
from something suitable for low pass power line filters to
coupling/mixing into the microwave ranges.
 
E

Eeyore

Jan 1, 1970
0
default said:
Working in the UPS field? I rather doubt it.

Given his name I looked at his headers to see if he was posting from India 9 (would
explain a lot) But *he's posting from an APC address* !!!!

Maybe he ought to go ask his colleagues / cow-orkers for a hint ?

Graham
 
T

Tim Wescott

Jan 1, 1970
0
mukesh said:
hi sir,

i am working in the UPS field .. i wanted to know that what is the max
freq we can choose for flyback converter ..... i am using the ferrite
core transformer . is there any limitation for freq ? what is the
max working freq for ferrite core transformer??????????
Look in the catalogs. You can get ferrite cores for much higher
frequencies than the ones you're using. The usual limitations on power
supply efficiency vs. frequency is parasitic capacitance and diode lag
effects, which don't come from the core. This capacitance makes it
harder to drive the FETs quickly, and the recovery times of the diodes
(should you use them) causes some lost energy each cycle. Dealing with
gate capacitance increases circuit complexity, as does eliminating the
diodes by using synchronous rectification.

Driving the frequency up is attractive because the core size goes up
roughly with the amount of energy it has to store, and the amount of
energy stored is roughly proportional to the power supply's power output
times one cycle time. This means that a higher switching frequency
means smaller cores.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google? See http://cfaj.freeshell.org/google/

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html
 
K

Kevin G. Rhoads

Jan 1, 1970
0
Given his name I looked at his headers to see if he was posting from India 9 (would
explain a lot) But *he's posting from an APC address* !!!!

Cut the intern some slack ;-)
 
R

Robert Baer

Jan 1, 1970
0
mukesh said:
hi sir,

i am working in the UPS field .. i wanted to know that what is the max
freq we can choose for flyback converter ..... i am using the ferrite
core transformer . is there any limitation for freq ? what is the
max working freq for ferrite core transformer??????????
Max "frequency" is very dependent on the core material, as the loss
of the core varies widly on type and material.
Next is the current and how the winding is done (litz, multifilar,
strip, etc).
And last, is how fast one can switch the current (actual turn on and
turn ooff times.
If one gets "fast" enough, then one should think RF "linear"
circuits; say class "C" driven ferrite transformers, where one tends to
see sine waves for drive and output, with complex conjugate drive at the
FET gates.
 
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