A rotational wearable energy harvester for human motion

This paper presented a rotational electromagnetic energy harvester to scavenge the human kinetic energy and convert into electrical energy. The harvester simply introduced a cylindrical stator and disk-shaped rotor, which are made of NdFeB. Without complicated movement mechanism, the stator and rotor, of a higher pair have theoretical line contact by magnetic attractive force. Therefore, the rotor can easily rotate around the stator, avoiding unnecessary surface friction. In this paper, the wearable energy harvester was attached on human's ankle and wrist for harvesting body motion energy, such as jogging and running at different speeds. The relative movement between the fixed electromagnetic coil array and rotational magnetic rotor can generate electricity efficiently. At a running speed of 8 km/h, the maximum voltage and average power density can reach to 1.92 V and 0.2 mW/cm3, respectively. This rotational non-resonant energy harvester could be potentially used as alternative power source for smart wearable devices, such as wristwatch, heart-rate monitor, smart helmet and so on.