HELP with Wireless power transmission of miniscule harvested energy

Thread Starter

JJoll

Joined May 7, 2013
49
Hi,
I am about to harvest a tiny amount of energy from a peltier device or mini hydraulic generator (I am predicting to be around 10mW) and I am planning to wirelessly transfer this energy to another point (to the receiving end about 1 cm away) but I cannot transfer the power with wires. It should be wireless! I was just wondering if this is even feasible, given the small amount of energy and power that I am trying to transfer? any suggestion how can I go about this only using off-the-shelf product?
I was personally thinking of maybe using LTC3108 (Ultralow Voltage Step-Up Converter and Power Manager)(http://www.linear.com/product/LTC3108) to step up my the voltage and just use some sort of induction energy transfer. But I need the transmitting part (the power generator , resonant circuit, coils and etc to be as small as possible [something like 2cm by 2cm by 4cm]). Any better idea? I have heard of radio frequency (RF) power transfer (used in a few implantable medical components: [http://media.sjm.com/newsroom/media-kits/fact-sheet-details/2014/CardioMEMS-Technology-Fact-Sheet/default.aspx ]) as well but I dont anything about it.

thanks in advance
 

tcmtech

Joined Nov 4, 2013
2,868
Why does it need to be physically isolated to begin with?

At 10 mW LED's and a tiny solar panel would be my first choice.
 

Thread Starter

JJoll

Joined May 7, 2013
49
Why does it need to be physically isolated to begin with?

At 10 mW LED's and a tiny solar panel would be my first choice.
the reason is that the power generation happens inside a tube (with diameter of around 3cm). And I need to extract this power inside the tube and send it/transmit it outside without puncturing the tube. I dont think the solar panel idea works because the tube is not perfectly clear. and led light probably wont pass through. but thanks for the idea.
 

tcmtech

Joined Nov 4, 2013
2,868
Sounds like the whole power generation part of the concept needs to be rethought.

More information on the design and concept for both the generation end and the power usage end is needed to come up with a more practical solution.
 

Thread Starter

JJoll

Joined May 7, 2013
49
Sounds like the whole power generation part of the concept needs to be rethought.

More information on the design and concept for both the generation end and the power usage end is needed to come up with a more practical solution.
thanks for the reply tcmtech. Following is the details of the project: I have a pipe (diameter is around 3Cm) and the water is flowing through it. The idea is that I want to use a very small dc motor to to utilize the hydraulic power and generate some energy and transmit it outside the pipe. Due to the low flow of water/liquid I think I can generate max a few mW (I am not sure though). The idea is that I have to show that on the destination I can get around 10mW of power. that I can use this method to power up a device that requires around 10mW (device is nearby and outside the pipe). I am not particulary trying to power up a specefic device, I am just trying to show that I can get around 10mW (or a little bit more or less) outside the pipe. let me know if you have more question. thanks again.
 

LesJones

Joined Jan 8, 2017
2,343
I would think that having a rotating impellor in the liquid flow with a number of magnets attached to it so the poles were close to the inner walls of the tube with coils around the outside of the tube to form a generator. The magnets should be arranged so that alternate N and S poles faced the outside of the tube. You may be able to find a permanent magnet stepper motor from a windup torch that you could modify.

Les.
 

tcmtech

Joined Nov 4, 2013
2,868
The idea is that I want to use a very small dc motor to to utilize the hydraulic power and generate some energy and transmit it outside the pipe.

Unless its some sort of special application motor that designed to be submerged in water it won't last very long. Same with any electronics as well.
 

LesJones

Joined Jan 8, 2017
2,343
Hi tcmtech,
For my idea I should have added that the rotating magnet inside the tube should be encased in resin. The coil assembly would be outside. If he could get the ferrite magnet from a submersible pond pump he could use that. It is possible that some types of pond pump could work as a turbine and he would get some AC induced into the coil which he could rectify to drive an LED. The original coaxial turbine idea came from thinking of these pond pumps.

Les.
 

tcmtech

Joined Nov 4, 2013
2,868
The bigger issue I see is simply that any internally mounted components are going substantially reduce the flow and or increase the backpressure in the pipe. Especially so putting a ~2 cm square object in a 3 cm round pipe.

That's where us knowing all the details note the system and intended use of the generated power are necessary. As of now it look nothing more than a poorly thought out shits and giggles concept with no real practical validity or application of any sort.

Especially so if the power put is is a very arbitrary 10 mW with absolutely no reference to what voltage it needs to be at or what it will be powering. If it's just a undefined 10 mW of power a simple Peltier device of the right size with a few degrees of temperature differential from one side to the other would be more than sufficient and would not need to be located inside the pipe.
 
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