Performance of a Voice Coil Actuator-Based Electromagnetic Vibration Energy Harvester under Base Excitation

Abstract

Abstract

Abstract This study presents a comprehensive experimental and numerical investigation of voice coil actuator-based electromagnetic energy harvesting structure under resonant and harmonic excitations. The proposed harvester consists of a two-degree-of-freedom (2-DOF) mechanical system integrating a linear voice coil actuator and a permanent magnet, designed to broaden operational frequency coverage through dual-resonance energy conversion. The internal resistance of the actuator is 3.7 Ω, and the system was tested under 13 different external load resistances ranging from 1.1 Ω to 1 MΩ to evaluate the optimal power generation. Experimental results demonstrate that the first and second resonance frequencies occur at 206 Hz and 544 Hz, respectively, closely matching the theoretical predictions. The maximum power output of 0.4821 mW was obtained at an optimal load resistance of 3.3 Ω, emphasizing the importance of load matching in maximizing energy harvesting power output. The harvested power exhibits a smooth, relatively broad peak around the optimal load matching region (R_L 2.3-5.7 Ω), closely aligned with the internal coil resistance (3.7 Ω), beyond which power drops significantly as the load deviates into high-impedance regimes. The findings confirm that operation near resonance significantly improves energy conversion performance, while the proposed harvesting structure demonstrates dual-resonance voltage generation capability across two distinct frequency bands. Furthermore, the results validate the lumped-parameter electromechanical model for accurately predicting the dynamic and energy harvesting behavior of voice coil-based systems, providing a practical framework for future vibration energy harvesting applications.