contactless power transfer 2

[maniacc]

hello

could somebody tell if there is a company wich sells systems for contactles power transfer?
i need to transfer about 80W-100W at 24V. input does not matter.
thank you.

 

[Skogsgurra]

Distance, movement and isolation requirements as well as environment needs to be specified before one can say anything about this.

Gunnar Englund

http://www.gke.org

 

[maniacc]

distance less 1cm
does not move, but has to be removable.
it should transfer power from a basestaion to a portable terminal.

 

[Skogsgurra]

That is usually done with two ferrite cores with coils where the transmitter is fed with a square wave in the 10 - 100 kHz range and the receiving coil has a rectifier and regulators as needed.

http://www.vahleinc.com/products/VahleCPS.html

has standard equipment for power transmissopn over short distances. They may be on the large side, but they probably have smaller devices as well. Siemens used to have good app notes about these systems. Cannot find them any more. Probably because Siemens Ferrite operation changed name to something that I cannot remember any more.


Gunnar Englund

http://www.gke.org

 

[maniacc]

EPCOS emerged from Siemens Matsushita Components, a joint venture founded in 1989 by Siemens and Matsushita. Since EPCOS went public on October 15, 1999, both former parent companies have remained important shareholders, each holding 12.5% of equity. EPCOS was floated on the Frankfurt and New York Stock exchanges simultaneously. Since March 2003, EPCOS has been one of the largest companies in the new TecDAX index of technology stocks.


maybe?

 

[Skogsgurra]

Yes, you are right. I have even visited Epcos in Munich. And still couldn't remember their name.


Gunnar Englund

http://www.gke.org

 

[VEBill]

80 to 100 watts is getting up there. If you're pumping out 100 watts of (for example) 100 kHz, then there might be issues with leakage into the RF spectrum. The system design should address this from the outset.

Also, the core halves are not going to be as physically small as normal contacts would be. Maybe several square cm of coupling area (a guess) to replace a tiny connector.

 

[maniacc]

thank you!
i even find the application notes you mentioned!

http://www.epcos.de/web/generator/W...,property=Data__nn.pdf;/Application_notes.pdf

i think this will bring me a step futher!

 

[maniacc]

@VE1BBL:

size does not matter.

but the leakage into the RF spectrum worries me.this might be a problem.
i did not find any papers concerning this issue?

 

[electricuwe]

Arround 1990 a lot of work on this topic was published by folks from Aachen Univerity. The system was used as a power transfer element in robotic applications.

See the following list of publications:

http://www.isea.rwth-aachen.de/Ww/english/index.html

look for publications from

Thomas Kalker
Albert Esser
Andreas Nagel

 

[VEBill]

"size does not matter."

There's a joke in there struggling to get out... ...but I'll pass this time.


The advantage of low frequencies (60Hz, 400 Hz, etc.) is that nobody cares if it leaks. The advantage of high frequencies (40kHz, 100kHz, etc.) is that the cores would be much smaller. There is probably a frequency in the middle that will give you reasonably small cores and still be below the range where anyone cares about RF leakage.

Also, watch out for annoying acoustic leakage as well.

Can your interface include shielding, or does it need to be smooth surfaces?

 

[maniacc]

size doe not matter( in a reasonable way;-) )

according my research a frequency around 80-100khz should be used to achiev a good performance.
in this phase of the project the surface can have every shape needed.

 

[ScottyUK]

I did some work for ERA Technology in Leatherhead a few years ago using this technique. We had a demonstrator which could transfer about 5kW across half an inch or so. The prospective application was the offshore or sub-sea industries. The device I was developing was much smaller, being intended for non-contact compact fluorescent lamps. The biggest of these were approaching the power range you are looking for. The prototype was quite successful. I don't know if they licensed any of the designs for manufacture.

The concept was known as 'CETS' or Contactless Energy Transfer System, with my bit being known as 'CETS for CFL'. I don't know who is still there - the department was BC84 Power Electronics & Drives Group who might be able to help.

http://www.era.co.uk

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