Finite Element Simulation for Predicting the Magnetic Flux Density for Electromagnetic Vibration Energy Harvester †

The current revolution in the field of electromagnetic vibration energy harvester requires that both wireless sensor nodes and relevant power sources be cost- and size-optimized while ensuring that, during design/fabrication of the sensor’s power sources, the power deliverable to the sensors be maximum. Flux density dependency on the nature of the magnetic coupling material of VEH magnet-coil transducer is well reported while reports on size-optimized but improved performance in the VEH is available. This paper presents on the realization of an approach to ensure an accurate prediction of size-optimized but maximum power output on the electromagnetic transducer of a VEH. The adopted approach justifiably verifies the geometrically determined flux density on a Finite Element Magnetic Method Software (FEMM) on the permanent magnet (NdFeB N52) as a basis for optimization. An empirical formula—which predicts size-optimized flux density and could be used to predict the performance of a miniature energy harvester for wireless sensor nodes application—was formulated. For the geometry presented in this work, where (Formula presented.) and (Formula presented.) are the effective length and turns on the reference coil, the magnetic flux density, coupling coefficients, coil width and transducer thickness were predicted to optimize at 0.4373 T, 0.3978 (Formula presented.) Tmm, 4.00 mm and 18.40 mm, respectively, with all corresponding to instances when the flux density per unit volume on the coil was approximately 0.4373 (Formula presented.) T (Formula presented.). The above optimized values were measured on magnet-coil geometry with the smallest overall thickness. However, in comparison to other models, the coil thickness in the optimized geometry was not the least.