A non-resonant rotational electromagnetic energy harvester for low-frequency and irregular human motion

There is an abundance of low-frequency and irregular human motion energy that can be harvested. In this work, a non-resonant rotational electromagnetic energy harvester (REH) for scavenging low-frequency (<10 Hz) and irregular human motion is presented. The energy harvester simply introduces a cylindrical stator and a disk-shaped rotor forming a movement of a higher pair. Without any complicated transmission mechanism, the rotor can easily rotate around the stator by magnetic attractive force. Driven by a broadband frequency vibration, the magnetic rotor is coupled with surrounding wound coils to operate electromagnetic energy harvesting. Theoretical and experimental investigations of the REH are studied, and numerical simulations show good agreement with the experimental results. The treadmill tests at various motion speeds are performed to demonstrate the advantage of the REH in harvesting energy from irregular human motion. At a driving frequency of 8 Hz, the electromagnetic coils can provide the maximum power of 10.4 mW at a load resistance of 100 Ω. The REH exhibits outstanding output performance and has potential applications for powering intelligent wearable or portable electronic devices.