A Novel Centrally Symmetric Spiral-Nested Piezoelectric Energy Harvesting System and Its Management Circuit

Abstract

To realize high power density, low-frequency, multidirectional energy harvesting, and efficient energy storage management, a piezoelectric energy harvesting system comprising a centrally symmetric spiral-nested piezoelectric energy harvester (CSS-PEH) and an energy management circuit is proposed in this work. The harvester features a doubly clamped outer beam and a nested dual-spiral inner beam, while the management circuit integrates a self-powered parallel synchronized switch harvesting on inductor (SP-PSSHI) rectification circuit, BQ25570 IC, and supercapacitor. A three-degree-of-freedom (2-DOF) lumped parameter model and an electromechanical coupling model are established to analyze the frequency response and output characteristics. The measured results show that the CSS-PHE has resonant frequencies at 12.8 and 17.2 Hz, with corresponding open-circuit voltages of 73.5 and 38.7 V. Meanwhile, the SP-PSSHI rectified series circuit achieved maximum output powers of 6.23 mW with the normalized power density (NPD) of $32.4~\mu $ W $\cdot $ g ${}^{-{2}} \cdot $ mm ${}^{-{3}}$ ; the SP-PSSHI rectified parallel circuit delivered the maximum output power of 3.21 mW with the NPD of $21.6~\mu $ W $\cdot $ g ${}^{-{2}}\cdot $ mm ${}^{-{3}}$ . The energy management circuit enables supercapacitor charging up to 4.05 V while maintaining stable 3.3-V dc output. Furthermore, the CSS-PEH demonstrates multidirectional energy harvesting capability. Therefore, this piezoelectric energy harvesting system provides stable power supply solutions for many fields, such as intelligent transportation energy harvesting, wireless sensor networks, and so on.