A tunable rotational energy harvester exploiting a flexible-clamping piezoelectric beam by deploying magnetic repulsive force

This paper presents a tunable rotational energy harvester exploiting a flexible-clamping piezoelectric transducer by deploying magnetic interaction force to enhance the robustness and environmental adaptability. The flexibleclamping rotational piezoelectric energy harvester (FC-RPEH) is characterized by the simultaneous function of frequency tuning and amplitude limiting. An analytical model was established and simulated using Duhamel's integral principle to obtain the influence of structural parameters on output characteristics of the harvester. Then, an experimental prototype of the FC-RPEH was fabricated and tested to verify its feasibility. The research results showed that there were multiple effective rotational speeds where the vibration amplitude and output voltage could reach peaks. Moreover, the effective rotational speeds, the number of effective speeds, as well as their corresponding output voltages depended on excitation ratio, the ratio of clamping length and the clamping distance. With the decrease of clamping distance and the increase of excitation magnets and clamping length, the effective rotational speeds were increased. Also, the desirable resonant frequency could be obtained by adjusting the excitation magnets, clamping length, and clamping distance. And their reasonable combinations could effectively broaden the bandwidth to adapt to different ranges of rotational speed. Besides, there was a matched load resistance of 200 k omega to achieve the maximum power of 9.95 mW for the FC-RPEH.

Automated summary

This paper presents a tunable rotational energy harvester that utilizes magnetic interaction force to enhance robustness and environmental adaptability. The harvester has the simultaneous functionality of frequency tuning and amplitude limiting. An analytical model is established and simulated to analyze the influence of structural parameters on output characteristics. Experimental results verify the feasibility of the proposed harvester, which demonstrates multiple effective rotational speeds and adjustable resonant frequency to adapt to different rotational speed ranges. The maximum power of 9.95 mW is achieved with a matched load resistance of 200 kΩ.