System-Level Model and Simulation of a Frequency-Tunable Vibration Energy Harvester

Area of Science:

• Energy Harvesting
• Mechanical Engineering
• Materials Science

Background:

• Vibration energy harvesting is crucial for powering autonomous systems.
• Industrial applications often exhibit complex and varying vibration frequencies.
• Existing harvesters may have limited operational bandwidth or require manual tuning.

Purpose of the Study:

• To present a macroscale, multiresonant vibration energy harvester with frequency tunability.
• To enable autonomous adaptation of the harvester's resonance frequency to ambient vibrations.
• To enhance the operative harvesting frequency range for industrial applications.

Main Methods:

• Magnetostatic actuation using external magnets on linear stages for frequency tuning.
• System-level modeling and reduced-order modeling derived from finite element analysis.
• Implementation of a maximum-voltage tracking control algorithm for tuning.
• Experimental characterization of the harvester's performance.

Main Results:

• The harvester features dual fundamental modes in the 50-100 Hz range, suitable for industrial vibrations.
• Autonomous adaptation of resonance frequency to dominant ambient frequencies was demonstrated.
• Experimental power output of 500 µW was achieved at 0.5 g excitation at 63.3 Hz and 76.4 Hz.
• Design optimization led to closer resonance frequencies and improved performance.

Conclusions:

• The proposed tunable vibration energy harvester offers a wider operative frequency range and autonomous adaptation.
• The device shows significant potential for powering sensors and devices in industrial environments.
• Further optimization can enhance power output and broaden applicability.