# Maximum theoretical power from piezoelectric harvesting

• juanitopapito
Voltage-Output-and-ResistanceYou need to know the output resistance of the piezo sensor and you also need to know how much voltage it generates at that frequency for a given force input. Here is an example of the chart you need for whichever accelerometer you have:http://www.ni.com/white-paper/3807/en/If your goal is to generate power, I'd pick one that resonates at 200hz or whatever frequency the input from the machine will be.

#### juanitopapito

Hi there...
I have an application where I know the vibration frequency/force/acceleration of the source...

How can I find the maximum theoretical power output (in mw/watts...) of a tuned piezo where its resonance is the same as the source vibration frequency...

juanitopapito said:
Hi there...
I have an application where I know the vibration frequency/force/acceleration of the source...

How can I find the maximum theoretical power output (in mw/watts...) of a tuned piezo where its resonance is the same as the source vibration frequency...
Welcome to the PF.

Just try looking at typical piezo datasheets for parts that fit your application.

What are the frequency and amplitude of your application?

berkeman said:
What are the frequency and amplitude of your application?

Consistent 200 hz...

Typically 0.1 G acceleration on a 1 kg object (so 20 G on say a 5 gram harvester...)...sometimes it is 1 G on the 1 kg, but rarely..

Is there any way I can get 1 W+ of energy from it using a piezo or other vibration harvester? especially on the low end so it is consistent... Does not have to be a commercially available product, even experimental things that are out there...

juanitopapito said:
Is there any way I can get 1 W+ of energy from it using a piezo or other vibration harvester?

again, as Berkeman said, without knowing the properties of the sensor, the answer to that is unknown

Dave

davenn said:
again, as Berkeman said, without knowing the properties of the sensor, the answer to that is unknown

Dave

what else is necessary?...

juanitopapito said:
what else is necessary?...

davenn said:
without knowing the properties of the sensor, the answer to that is unknown

you can't seem to give those, so you question is still unanswerable

D

juanitopapito said:
what else is necessary?...
How are you going to couple the piezo to the object(s)? Can you get a straight compression-expansion motion on the piezo? Or will it be more of a bending moment?

What piezo do you plan on using? Can you link to the datasheet? Have you looked at Kynar Piezo Film?

http://www.piezotech.fr/fr/2-products-piezoelectric-polymers/news/news-31-p-vdf-trfe-piezoelectric-films.html [Broken]

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berkeman said:
How are you going to couple the piezo to the object(s)? Can you get a straight compression-expansion motion on the piezo? Or will it be more of a bending moment?

What piezo do you plan on using? Can you link to the datasheet? Have you looked at Kynar Piezo Film?

http://www.piezotech.fr/fr/2-products-piezoelectric-polymers/news/news-31-p-vdf-trfe-piezoelectric-films.html [Broken]

I'm looking at piezos...I plan to use a cantilever (probably)...

How can I tell how much force it would take on each piezo to generate a watt...and what about the frequency...?

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Suppose you have a predefined volume of piezoelectric (10cm^3). What is the maximum harvested power using piezoelectric?

Si14 said:
Suppose you have a predefined volume of piezoelectric (10cm^3). What is the maximum harvested power using piezoelectric?
What reading have you done on this so far? What shape would be the best for harvesting, given that volume?

juanitopapito said:
I'm looking at piezos...I plan to use a cantilever (probably)...

How can I tell how much force it would take on each piezo to generate a watt...and what about the frequency...?

You need to know the output resistance of the piezo sensor and you also need to know how much voltage it generates at that frequency for a given force input. Here is an example of the chart you need for whichever accelerometer you have:

Here is more information on accelerometer selection. http://www.ni.com/white-paper/3807/en/ If your goal is to generate power, I'd pick one that resonates at 200hz or whatever frequency the input from the machine will be.

When you know the voltage output per-G of acceleration at a given frequency, and you also know the output resistance, you can then calculate wattage.

http://www.wikihow.com/Calculate-Wattage