Autonomous Resonance‐Tuning Mechanism for Environmental Adaptive Energy Harvesting

Abstract

An innovative autonomous resonance‐tuning (ART) energy harvester is reported that utilizes adaptive clamping systems driven by intrinsic mechanical mechanisms without outsourcing additional energy. The adaptive clamping system modulates the natural frequency of the harvester's main beam (MB) by adjusting the clamping position of the MB. The pulling force induced by the resonance vibration of the tuning beam (TB) provides the driving force for operating the adaptive clamp. The ART mechanism is possible by matching the natural frequencies of the TB and clamped MB. Detailed evaluations are conducted on the optimization of the adaptive clamp tolerance and TB design to increase the pulling force. The energy harvester exhibits an ultrawide resonance bandwidth of over 30 Hz in the commonly accessible low vibration frequency range (<100 Hz) owing to the ART function. The practical feasibility is demonstrated by evaluating the ART performance under both frequency and acceleration‐variant conditions and powering a location tracking sensor.

A broadband piezoelectric vibration energy harvesting system based on sensorless direct resonance tuning technique

“…Additionally, the EH performance drops dramatically when the operating frequency deviates from the resonance point [13]. In order to broaden the operating frequency band of a PEH, various solutions have been proposed, mainly including energy harvester array (EHA) methods [14,15,16,17], nonlinear energy harvester (NEH) methods [18,19,20,21,22,23] and inherent frequency adjustment (IFA) methods [24,25,26,27,28,29,30,31]. Based on EHA methods: arraying energy harvesters with different inherent frequencies is the easiest way to obtain a broadband PEH system.…”

“…Many types of EHA have been designed, including an ensemble of cantilever beams with a proof mass [14], a connection patterns among piezoelectric bimorphs [15], a magnetically coupled PEH array [16] and others. However, EHA is limited in continuous frequency adjustment and the power density of EHA is quite low [17]. Based on NEH methods: the NEH has wide and steady bandwidth [18,19].…”