Bi-Mode Electromagnetic Energy Harvester and Energy Management Strategy for Long-Time Monitoring Sensor

This paper introduces a bi-mode electromagnetic energy harvester (BEEH) designed to harvest energy from micro-vibrations in both translational and rotational modes. The vibration amplitude can be amplified by the vibrator with a suspending structure, and two groups of magnet sets are designed to supply magnetic fields for the coil. The finite element simulations are employed to obtain the optimal magnetic field configuration. An analytical model of the magnetic field and system output of the BEEH is developed, and its accuracy is validated through comparative analysis. In order to improve the output efficiency and stability, an energy management strategy and the corresponding circuit modules are designed. To validate the design and modeling, a prototype of the BEEH is fabricated, and experimental results confirm that the two operational frequencies (100[Formula: see text]Hz and 110[Formula: see text]Hz) align well with the theoretical predictions. The optimum load resistance for the harvester is approximately 10[Formula: see text]k[Formula: see text], and the maximum output power is up to 28[Formula: see text]mW at 100[Formula: see text]Hz under vibration excitation with an amplitude of 10[Formula: see text][Formula: see text]m. Furthermore, the BEEH demonstrates the capability to power multiple loads, thereby validating its efficiency in harvesting energy from micro-vibrations for long-time monitoring applications.