500 Watts DC to DC converter, 100 Khz Switching Frequency

[nonsinusoidal]

I am in search on how to determine the primary and secondary conductor sizes for a 500 Watts, 100 KHz switching frequency, DC to DC converter. The configuration of the DC to DC converter will be a push pull configuration Circuit. A 12 volt DC voltage will be utilized for the primary side of the high frequency Converter. The secondary voltage will be 370 Vpp. I am considering to use a transformer wound with litz wire. I will be selecting the core of the transformer and the lintz wire. Can anyone advice on how to proceed on the calculations to achieve the above mentioned task?

 

[itsmoked]

It's non-trivial.. The wire type, the core, the core power ability, the core material, the core style, and the winding method to list but a few variables each are important. Your best bet would be to see if the core makers have a design guide to help you. Perhaps they even an on-line calculator to help you sort out some of this.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[ScottyUK]

Getting the core right is probably the single most important step as it constrains almost every other decision relating to the transformer design. To make an informed choice you'll have to do a bit of reading up: see if you can find a copy of the book 'Soft Ferrites' by Edgar Snelling. It's been out of print a while and the ferrite materials are not the most modern types but the explanations and detail design methods are first class. The old Philips databook 'Soft Ferrites', no MA01 is also useful. Ferroxcube, who bought that business when Philips exited the component market, have continued publication of the book and appear to have updated it quite a lot.

The book by Snelling I mentioned is the top of Ferroxcube's reference list on page 56, and another book by the same author takes second place: draw you own conclusions about the quality of Snelling's work. There are quite a few other books listed which are worth at least checking out.

FWIW, at 500W from 12V at 100kHz you will probably be better using a tape or foil LV winding.


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If we learn from our mistakes I'm getting a great education!

 

[OperaHouse]

Is there a particular reason you would want to build this. Besides the commercial modules, there are 12 to 120VAC inverters that are easily modifiable to create this voltage.

 

[Comcokid]

You might try one of the books by Colonel McLyman on transformer design, or download application note AN109 by CoreMaster. Note that in this app note, the wire gauge calculated assumes a sinewave, 100khz squarewave will have harmonics which means you will want smaller wire still. McLyman's books will provide the coefficients for the magnetic cores made by other companies or for cores other than toridial.

Get litz wire, or parallel litz wire to get the cir-mils you calculate.

Or do as OperaHouse suggested. A 12VDC to 120VAC sinewave inverter will have a first stage output voltage of about 185VDC. A 12VDC to 230VAC sinewave inverter will have a primary stage very close to what you're looking for.

 

[nonsinusoidal]

Thank you for your prompt responses. I will do my research and build the dc to dc converter. It is a project which I have been working on to maintain the fundamentals of engineering fresh in my mind.