Abstract
Energy harvesting from human motion is expected to the energy source for wearable devices. Although the energy density of human motion is high, the frequency of it is a few Hz, which does not match the conventional energy harvester. Due to this, the size of harvester tends to become large in order to get high output. This paper presents an electrostatic induction energy harvester which can generate high power at low frequency in order to power the mouthguard type sensor. To embed into the mouthguard type sensor, the total thickness of the harvester should be less than 0.2 mm to reduce the discomfort. Furthermore, the final goal of power generated of the harvester was set to a few tens of μW. The proposed harvester consists of electrets that can hold a quasipermanent charge on its surface, dielectric elastomers and electrodes. The mechanical energy applied by the biting force is converted to electrical energy by electrostatic induction. The parametric study of the harvester based on the equivalent circuit model was conducted to maximize the power generated. According to the calculation results, the harvester can achieve 22.7 μW with a load resistance of 570 MΩ, which met the requirements for the mouthguard type sensors. The fabrication and evaluation of the harvester based on the calculation results will be conducted in the future work.
