A MEMS Piezoelectric Vibration Energy Harvester Based on Trapezoidal Cantilever Beam Array

This paper reports a novel MEMS piezoelectric vibration energy harvester based on trapezoidal cantilever beam array (TCBA-PVEH), which mainly composed of a piezoelectric array beam and a mass block. The open-circuit voltage ( $V_{oc}$ ), the optimized load voltage ( $V_{opt}$ ) and the optimized load output power ( $P_{opt}$ ) of the TCBA-PVEH at 0.5g acceleration can reach 10.36 V, 6.68 V and $12.51\ \mu \mathrm{W}$ , respectively. The experimental results show that the TCBA-PVEH has smaller bending stiffness and larger piezoelectric strain energy per unit area than the rectangular cantilever beam array based PVEH (RCBA-PVEH), thus having lower resonance frequency and better electrical output. We also establish and analytically solve the electromechanical coupling dynamic model of PVEHs with variable cross-section cantilever beam. The proposed model lays an important theoretical foundation for structural optimization design, performance improvement and output prediction.