Enhancing the Magnetic Flux Density in Rotational Electromagnetic Energy Harvester

Rotational electromagnetic energy harvester is a kind of device with practical value that converts kinetic energy into electrical energy. This work investigated the effect of pure iron plate dimension on the magnetic flux density at spatial position of the coil in a rotational electromagnetic energy harvester. Increasing the magnetic flux density at spatial position of the coil in a rotational electromagnetic energy harvester is an effective means to enhance the output power of harvester, and the reasonable configuration of magnetic materials plays a crucial role during this process. In Finite Element Magnetic Methods (FEMM) software, models were established for different cases to obtain the average magnetic flux density in specific cross-sectional areas during the operating state of harvester. This work indicated that if a single coil in the harvester is separated into two series connected coils and they are closer to magnets, the magnetic flux density value will be increased to a certain extent. If a pure iron plate is set between two series connected coils, as width and height of the pure iron plate are appropriate, the magnetic flux density value can be increased by up to 8.5%, and correspondingly, the output power of the energy harvester can be increased by 15.2%. Therefore, it would be advantageous to configurate the rotational electromagnetic energy harvester with appropriately sized pure iron plates.