Electromagnetic Energy Harvesting via Self-Excited Resonance from Extremely Low-Frequency Vibrations

Abstract

This paper presents an electromagnetic energy harvester (EMEH) using gravity-induced self-excited vibrational resonance. The EMEH is capable of harvesting vibration energy below 1 Hz. The structure is a cantilever-mass system, and the mass is comprised of a magnet array and its support. The EMEH is excited by the gravity of the cantilever-mass system intermittently sliding down along a central hub. To explain the output performance of the EMEH visibly, we formulated the motion process and built an eight-stage dynamics motion. The effect of the cantilever thickness on the open-circuit voltage is discussed, and the results agree with the theoretical description well. Additionally, to demonstrate the output performance of the harvester, more experiments were performed, i.e., matching impedance, charging capacitors, and powering light emitting diodes (LEDs). The EMEH delivers a maximum instantaneous output power of 144.1 mW at a beam thickness of 1 mm. For charging experiments, 47 LEDs were successfully lighted up in real-time. The high performance of the gravity-induced resonance scheme indicates tremendous low-frequency application potential.