Dynamic modeling and experimental study of multi-coil composite core energy harvester

To improve the output performance and working bandwidth of the magnetic levitation energy harvester, a new structure of multi-coil composite core energy harvester was proposed and verified by numerical simulation and experiment. Firstly, the working mechanism of the energy harvester was analyzed. The dynamics model and COMSOL Multiphysics finite element analysis model were established to study the influence of magnetic field and coil position on the output characteristics of the energy harvester. Then, an experimental platform was built to verify the proposed new energy harvester, and the influence of coil position on the output power of the energy harvester was explored. Three kinds of coil thicknesses, two kinds of coil winding directions, six kinds of coil connection modes and two kinds of magnet distribution experiments were designed. Finally, the influence of suspended core mass on output performance was analyzed, and the energy harvester with or without magnetic liquid was tested by sweeping frequency to evaluate its output performance. The experimental results show that the magnetic field near the coil can be enhanced effectively, and the output performance of the whole system can be improved by the magnet mutual repulsion energy harvester with coil connection mode CM1 in a consistent coil direction. With the increase of composite core mass, the output voltage and power of the energy harvester also increase, but the peak frequency decreases. Compared with the energy harvester without magnetic liquid, the output power performance of the designed multi-coil composite core energy harvester is significantly improved by 29%, and the frequency bandwidth growth rate is 73%. The normalized power density can reach 134.26 μWcm−3g−2. The new structure of the multi-coil composite core provides important reference significance for designing a more efficient magnetic levitation energy harvester.