Vibro-Shock Dynamics Analysis of a Tandem Low Frequency Resonator—High Frequency Piezoelectric Energy Harvester

Abstract

Frequency up-conversion is a promising technique for energy harvesting in low frequency environments. In this approach, abundantly available environmental motion energy is absorbed by a Low Frequency Resonator (LFR) which transfers it to a high frequency Piezoelectric Vibration Energy Harvester (PVEH) via impact or magnetic coupling. As a result, a decaying alternating output signal is produced, that can later be collected using a battery or be transferred directly to the electric load. The paper reports an impact-coupled frequency up-converting tandem setup with different LFR to PVEH natural frequency ratios and varying contact point location along the length of the harvester. RMS power output of different frequency up-converting tandems with optimal resistive values was found from the transient analysis revealing a strong relation between power output and LFR-PVEH natural frequency ratio as well as impact point location. Simulations revealed that higher power output is obtained from a higher natural frequency ratio between LFR and PVEH, an increase of power output by one order of magnitude for a doubled natural frequency ratio and up to 150% difference in power output from different impact point locations. The theoretical results were experimentally verified.

Shape optimization of the active element for vibration energy harvesting

“…The impact-coupling configuration is examined in [23]. The active element of the VEH has a different lower and higher natural frequency ratio.…”

“…of state (21) can be solved using one of the methods of the numerical integration of the ordinary differential equations and restrictions in Eqs. (21) and (23) for each of the discrete steps should be established. This shows the above disadvantage, that a large amount of time-based constraints has to be dealt with.…”

Review of vibration-based energy harvesting technology: Mechanism and architectural approach

“…61 The lowest b/a ratio, obtained from a triangular beam, produced higher strain and voltage, compared with the highest ratio rectangular beam. 66 The aforementioned cantilever EHs, however, are efficient only when the resonance and excitation frequencies are equal; this is uncontrollable due to random ambient vibration. 61 The relationships between choice of materials and beam thickness are demonstrated in Figure 18D.…”

“…62,65 Thus, the frequency up-conversion technique was adopted in certain scenarios instead if higher energy was required. 66 The aforementioned cantilever EHs, however, are efficient only when the resonance and excitation frequencies are equal; this is uncontrollable due to random ambient vibration. One solution is to use multiple cantilevers or an array thereof, in which the beams are of varying lengths or tip masses, such that each has a different RF and the EH bandwidth is broader, 63,67,68 as illustrated in Figure 18C.…”

All‐Inorganic‐State Fabric Lead‐Free Piezoelectric Nanogenerators

“…[10] Among diverse piezoelectric generators, there have been some reports for flexible piezoelectric energy harvesters (also called "nanogenerators" when nanomaterials are involved) using lots of materials and processes to propose new concepts from biological to constructional applications. [11][12][13][14] Even though the triboelectric energy harvesting principle has been recently studied to maximize voltage output performance, [15][16][17] piezoelectric materials and devices are still the highly prospective candidate for mechanical energy harvesting devices due to their definite material mechanisms, existing industries, and intrinsically robust properties apart from extrinsic operation environments. [18,19] Although the developed flexible energy harvesters have supported and established piezoelectric wearable configuration, they should be attached as patch-type or non-woven devices, not real cloth-like features, which hinders our free movement and physical activity.…”