Damping effect in piezoelectric energy harvesting systems

[nabs16]

Hi,

I have to make a report on an energy harvesting system using piezolectric materials by comparing two methods each other which are: the standard technique (rectifier bridge+filtering capacitance) and the nonlinear technique, by adding to the standard device a switch and an inductor in parallel of the piezoelectric element (SSHI technique) to optimize the electromechanical conversion.

According to the different articles, the nonlinear technique is very efficient in weak coupling (constant displacement amplitude) but not for larger electromechanical coupling factors due to a damping effect caused by the SSHI technique. What is concretly the damping effect ? why it doesn't occur using the standard technique ?

I know that the electromechanical coupling factor is low for weakly coupled structure and high for strongly coupled strucutre but i don't understand what it physically means. How can we obtain these two types of structures in laboratory ?

Thanks.

 

[jrmichler]

Hi,

What is concretly the damping effect ? why it doesn't occur using the standard technique ?

All energy harvesting techniques remove energy from the system. The energy that is removed damps vibrations. More efficient energy removal causes more damping.

Another way to look at it is that energy harvesting is a form of active vibration control, where the energy removed is put to use instead of dissipated.

 

[berkeman]

comparing two methods each other which are: the standard technique (rectifier bridge+filtering capacitance) and the nonlinear technique, by adding to the standard device a switch and an inductor in parallel of the piezoelectric element (SSHI technique) to optimize the electromechanical conversion.

According to the different articles, the nonlinear technique is very efficient in weak coupling (constant displacement amplitude) but not for larger electromechanical coupling factors due to a damping effect caused by the SSHI technique. What is concretly the damping effect ? why it doesn't occur using the standard technique ?

Can you post links to the reading you have been doing about this? That would be a big help. Thanks.

 

[nabs16]

Yes of course. Sorry I should have posted the links in the first message.

http://ieeexplore.ieee.org/document/1428041/
https://www.sciencedirect.com/science/article/pii/S0924424705006151

 

[berkeman]

Yes of course. Sorry I should have posted the links in the first message.

http://ieeexplore.ieee.org/document/1428041/
https://www.sciencedirect.com/science/article/pii/S0924424705006151

Those appear to be behind pay walls, and most of my quick search results are too. Are there any review articles available? I'm interested in the switching architecture... Thanks.

 

[anorlunda]

I found this: http://www.psma.com/sites/default/f...energy-harvesting-using-piezoelectric-dev.pdf showing what @berkeman asked about.