Energy harvesting from AC motor: components selection

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vilson_garciaa

Joined May 6, 2018
8
I'm trying to set up an energy harvesting system from the external magnetic flux generated by AC electrical machine (specifically, an induction motor). The goal is for the energy harvesting system to power a sensor, ESP8266 more specifically, and/or store it in a battery.

I already made a coil and would like your help to choose the integrated circuit component for AC/DC converter and the boost converter. It would be to convert 20mV ~ 100mV from AC to DC and then a boost converter to raise it to 3.3V and power the ESP8266 and/or store it in the battery.

I looked for an integrated circuit component that converts a voltage of approximately AC/DC and that is a voltage step-up converter, all in one component, but I didn't find it. I thought about using an op-amp and building a precision rectifier, but I don't know if it would work because it would need a power supply for the op-amp unless I use the battery for power. And then I would use an LTC3108, is that the best option? Because it is important that it is very efficient, as it is ultra-low power.

Do you guys recommend a component that already does everything? Or a very efficient rectifier and boost converter?
 

Audioguru again

Joined Oct 21, 2019
4,793
The voltage is too low to convert the AC into DC.
Use a transformer to boost the AC voltage but then the current will be reduced by the same multiplication.
Then the battery will need to be charged for weeks for it to power the low current devices for a few seconds.

You need to spin the Alternator much faster to produce some useable voltage and current.
A guy put a computer fan on his bicycle for it to generate power for some LEDs but it produced not nearly enough power.
He needed and tried a huge fan as a generator but it made pedaling the bicycle very hard work for it to light some LEDs.
He ended up buying disposable batteries like everybody else.
 

MrSalts

Joined Apr 2, 2020
1,832
Bob Marley wrote...
"If she's amazing, she won't be easy."

Many people, just as smart as you, have put thousands of hours into this topic and failed. If you get one step closer, you're a genius. If you think you'll succeed because you asked a bunch of old guys on a website and expect to have an answer this evening snd a working prototype by Wednesday - well, not a genius. You're not the first to have this idea and you won't be the last.

I'll paraphrase a later line in the same Marley song...
"Truth is, every project is going to hurt you; you just gotta find the ones worth suffering for.“

I'm not sure this one is worth the suffering.
 
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