Enhancing low-frequency vibration energy harvesting using Negative Stiffness Inertial Amplifiers

Conventional piezoelectric energy harvesters (PEHs) struggle to capture energy from low-frequency vibrations due to their intrinsic stiffness, limiting their applicability in real-world scenarios. The integration of Negative Stiffness Inertial Amplifiers (NSIAs) with cantilever bimorph PEHs enables a reduction in effective stiffness and amplification of dynamic mass, thereby enhancing low-frequency energy harvesting efficiency. A mathematical framework for NSIA-based energy harvesters is developed, analysing two circuit configurations (with and without an inductor). Key parameters, including stiffness ratio, mass ratio, and amplifier angle, are optimised. The harvested power is evaluated under both harmonic and random excitations. The proposed NSIA-integrated system achieves 99.97% higher power output compared to conventional harvesters. The inclusion of an inductor further enhances power generation at higher frequencies. Comparative analysis with traditional inertial amplifiers (IAs) shows that NSIAs outperform IAs by nearly two orders of magnitude. The findings demonstrate the transformative potential of NSIAs in vibration energy harvesting (VEH), offering a scalable and efficient solution for self-powered sensing, structural health monitoring, and industrial IoT applications.