ferrite or iron powder transformer

[Jamie Morken]

Hi,

I am designing a 3kW switching power supply and am wondering about if
a 30kHz ferrite or iron powder transformer with at least 4 taps per
side is an off the shelf item or if it would need to be custom wound?
I have looked around at some of the transformer manufacturers but
haven't yet seen a ferrite/iron powder core that is at this power level.

cheers,
Jamie

 

[Tim Wescott]

Hi,

I am designing a 3kW switching power supply and am wondering about if
a 30kHz ferrite or iron powder transformer with at least 4 taps per
side is an off the shelf item or if it would need to be custom wound?
I have looked around at some of the transformer manufacturers but
haven't yet seen a ferrite/iron powder core that is at this power level.

cheers,
Jamie

I would expect that not only would it be custom-wound, but quite the
challenge to get it right -- to the point where you'd want to be as much
of a transformer winding expert as a circuits guy to get the whole
shebang working, and you'd be trading off circuit topologies vs.
transformer designs during the design phase.

I'd be interested in seeing how it works out for you.

--

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

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

 

[Jamie Morken]

Hi Tim,

I would expect that not only would it be custom-wound, but quite the
challenge to get it right -- to the point where you'd want to be as much
of a transformer winding expert as a circuits guy to get the whole
shebang working, and you'd be trading off circuit topologies vs.
transformer designs during the design phase.

I'd be interested in seeing how it works out for you.

The best link I've found so far is:

http://www.inductech.com/inductor_design_company/high_frequency_magnetics.htm

cheers,
Jamie

 

[Paul Mathews]

Hi,

I am designing a 3kW switching power supply and am wondering about if
a 30kHz ferrite or iron powder transformer with at least 4 taps per
side is an off the shelf item or if it would need to be custom wound?
I have looked around at some of the transformer manufacturers but
haven't yet seen a ferrite/iron powder core that is at this power level.

cheers,
Jamie

You've told us very little about the requirements. Among the most
important are input and output voltage and current and available
airflow. Do you care about size, weight, cost, EMI, agency approvals?
30 kHz is not a particularly high frequency,but the power level is
high enough that many things must be considered in the design. Off the
shelf? Forget it.
Paul Mathews

 

[Jamie Morken]

Hi,

You've told us very little about the requirements. Among the most
important are input and output voltage and current and available
airflow. Do you care about size, weight, cost, EMI, agency approvals?
30 kHz is not a particularly high frequency,but the power level is
high enough that many things must be considered in the design. Off the
shelf? Forget it.
Paul Mathews

I have just started this project and don't know the input signal yet
very well, but the outputs of the power supply will be either 120VAC or
240VAC 50Hz or 60Hz. This is just an estimate so far. The input
voltage can vary widely from about 50V up to a max of about 500V.

topology is push pull fullbridge

primary 7 taps maximum 500V/7Amps 3.5kW max
secondary 5 taps maximum 340V/10Amps 3.5kW max

30kHz estimated frequency

multiple parallel transformers?

CSA/UL/CE approval are important

efficiency important


Jamie

 

[Frithiof Andreas Jensen]

Hi,




I have just started this project and don't know the input signal yet
very well, but the outputs of the power supply will be either 120VAC or
240VAC 50Hz or 60Hz. This is just an estimate so far. The input
voltage can vary widely from about 50V up to a max of about 500V.

topology is push pull fullbridge

Why? Half-bridge is easier to get to work especially at the 500 V.

primary 7 taps maximum 500V/7Amps 3.5kW max
secondary 5 taps maximum 340V/10Amps 3.5kW max

30kHz estimated frequency

multiple parallel transformers?

Multiple parallel power supplies would be much, much easier to handle,
especially if you get enough of them so that something half-way COTS can be
purchased (Above 300W or so, the market grows thin). The "taps" sort-of
alludes to multiple outputs anyway.

CSA/UL/CE approval are important

efficiency important

Can't be. Not with the 1:10 input voltage range!

 

[Robert Baer]

Why? Half-bridge is easier to get to work especially at the 500 V.




Multiple parallel power supplies would be much, much easier to handle,
especially if you get enough of them so that something half-way COTS can be
purchased (Above 300W or so, the market grows thin). The "taps" sort-of
alludes to multiple outputs anyway.




Can't be. Not with the 1:10 input voltage range!

For 50/60Hz, powder cores or ferrite cores are *not* recommended!

 

[Jamie Morken]

I would expect that not only would it be custom-wound, but quite the
challenge to get it right -- to the point where you'd want to be as much
of a transformer winding expert as a circuits guy to get the whole
shebang working, and you'd be trading off circuit topologies vs.
transformer designs during the design phase.

I'd be interested in seeing how it works out for you.

Well I have found that it will most likely be a planar transformer
design.. these things are amazing! No skin effect to worry about at
100kHz, less parasitics, more repeatability, smaller size, better
thermal characteristics.. any drawbacks, maybe cost?

cheers,
Jamie

 

[Eeyore]

Well I have found that it will most likely be a planar transformer
design.. these things are amazing! No skin effect to worry about at
100kHz, less parasitics, more repeatability, smaller size, better
thermal characteristics.. any drawbacks, maybe cost?

You need a multilayer pcb.

I agree they're remarkable though.

Graham