Method and device for energy harvesting

Abstract

A device (100) harvests energy from vibration and / or strain and utilises both capacitive (102a, 102b) and piezoelectric elements(105). The principle of operation is out-of-plane capacitive harvester,where the bias voltage for the capacitive element is generated with a piezoelectric element(105). The device utilizes a thin dielectric film (104) between the capacitor plates (102a, 102b) maximizing the harvested energy and enabling the harvester operation in semi-contact mode so that short circuits are prevented. For example when utilised in a wheel or the like, the capacitor is closed and opened at every strike or every turn of a wheel being thus independent of the harvester's mechanical resonance frequency.

Description

technical field [0001] The present invention relates to devices and methods for harvesting energy from vibration, strain, rotation and / or impact. Background technique [0002] Over the past few decades, the need to power eg wireless sensors has driven research activity on energy harvesting from the environment. The wireless communication capability cannot be fully utilized if power is provided through wires, or if batteries have limited operating time, bulky size, and heavy weight. [0003] The energy harvesting mechanism depends on the environment and application. Various energy sources have been proposed: light, heat (thermal gradients), strain, vibrations, electromagnetic fields, dynamics, air flow, pressure changes and radioactive materials, and also vibrations. [0004] One of the many investigated applications for energy harvesting is eg the automotive tire pressure monitoring system TPMS. Battery operated devices already exist on the market, but the harvester will ...

AI Technical Summary

Problems solved by technology

and many known harvesters are vulnerable to vibrations beyond the limits of intended use

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