Power Retention Under Excitation Variations in a Magnetically Levitated Electromagnetic Energy Harvester

Electromagnetic vibration energy harvesters with magnetic levitation are of interest for powering autonomous low-power devices due to their high output power; however, their narrow operating region makes them sensitive to changes in the parameters of external vibration excitation. This study investigates the effects of excitation frequency and base acceleration amplitude on the harvester’s output characteristics and evaluates mean power retention under combined deviations in these parameters. Numerical simulations of steady-state regimes were performed. Within prescribed neighborhoods of operating points, the minimum mean power and local relative power variation were determined. For the configuration considered, increasing the deviation bounds from ±0.2 Hz and ±0.2 g to ±0.8 Hz and ±0.8 g reduces the highest retained fraction of the global maximum power in the investigated domain from 77.73% to 24.58%, while the local relative power variation at the corresponding operating points increases from 16.46% to 66.48%. These results highlight the risk of selecting a high-power operating point near a sharp power-drop boundary, where excitation deviations can leave the load underpowered. The proposed analysis addresses this risk by evaluating the minimum mean power across the prescribed deviation range and identifying operating regions that satisfy the load’s power requirement.