High-Performance Spiral Piezoelectric Energy Harvester With Wraparound Proof Mass

In order to improve the output power density and achieve small footprint of piezoelectric energy harvester (PEH), a high-performance spiral PEH with wraparound proof mass is proposed in this work. The compact design of four concentric-type spiral beams shares a massive wraparound proof mass, which can generate greater vibration, thereby reducing the resonant frequency and increasing the output power. The output characteristics of this spiral PEH are studied, and the relationship of output voltage and output power with L-p (piezoelectric material length) is obtained. The output performance of this spiral PEHs with different L-p values is measured and compared with theoretical value. The measured results show that the output characteristics are the best when L-p is 18.75 mm. The maximum open-circuit output voltage is 47.8 V when the frequency of excitation is 107.2 Hz. The output power can reach 2635 mu W when the load resistance is 200 k Omega, which is in good agreement with the theoretical results with small error. Themultidirectional energy harvesting capability of this spiral PEH is also studied and measured. Therefore, this work can solve the tradeoff problem between high output power and small footprint of PEH and can meet the self-power requirement of micro wireless sensor systems.

Automated summary

This work proposes a high-performance spiral piezoelectric energy harvester (PEH) with wraparound proof mass to improve the output power density and achieve a small footprint. The compact design and shared additional mass of the spiral PEH results in greater vibration, reducing the resonant frequency and increasing the output power. Experimental results show that the output characteristics are the best when the piezoelectric material length (L-p) is 18.75 mm, with a maximum open-circuit output voltage of 47.8 V and an output power of 2635 mu W. The multidirectional energy harvesting capability of the spiral PEH is also studied and measured.