Out-of-plane Gap Closing Electrostatic Vibration Energy Harvester

This work is dedicated to experimental study of an electret-based electrostatic vibrational energy harvester with out-of-plane gap closing topology converting the mechanical vibration energy into electrical energy. It has been demonstrated that the maximal power produced by the eVEH at acceleration magnitude of 1 g is about $1.25\ \mu\mathrm{W}$. This value is reached under vibration frequency of 90 Hz and load resistance of $9\ \ \mathrm{M}\Omega$. Such value of the output power is comparable to that of other world-wide developments. The eVEH operation is studied in a pulse mode that is typical for wireless sensor networks nodes where they remain in standby mode for a long time to accumulate the converted energy. For this purpose the electronic switch with a low power consumption which can be closed after reaching a specific voltage across the storage capacitor has been implemented. It has been observed the LED luminescence at the moment of the switch closing.