Electret-Free Micromachined Silicon Electrostatic Vibration Energy Harvester With the Bennet’s Doubler as Conditioning Circuit

This letter presents for the first time experiments combining a previously reported microelectromechanical system electrostatic vibration energy harvester (e-VEH) and the Bennet´s doubler circuit. A self-limiting effect on the harvested power, which was not reported before on macroscopic e-VEHs, has been observed. This effect is due to the nonlinear dynamics of the system and to the self-increase of the electromechanical damping that is typical for e-VEHs. With a few volts of initial precharge, the Bennet´s doubler progressively increases the voltage across the transducer´s terminals up to 23 V, where saturation occurs. A power of 2.3 μW is available for a load, when the harvester is excited by 1.5 g at 150 Hz of external acceleration.