A piezoelectric–electromagnetic hybrid flutter-based wind energy harvester: Modeling and nonlinear analysis

This paper presents a piezoelectric–electromagnetic hybrid flutter-based energy harvester (HFEH), where the piezoelectric part and electromagnetic part are coupled with each other by magnetic forces. The working principle is explained in detail and the corresponding theoretical model of the HFEH is established based on Lagrange's equations, Newton's second law, Kirchhoff's law, a semi-empirical nonlinear aerodynamic model, and a magnetic dipole model. The advantages of the HFEH, output performance, and nonlinear output characteristics under different magnet distances and load resistances are analyzed. Results show that the cut-in wind speed and the output power of the HFEH are, respectively, lower and higher than those of the typical flutter-based piezoelectric energy harvester (FPEH). When the distance between magnets A and B and that between magnets C and D is small, the amplitude jump phenomenon occurs, and the electromagnetic part has a satisfactory output power near the jump points. The output power of the piezoelectric part and the electromagnetic part of the HFEH, respectively, reaches 1.35 mW and 36.63 mW at a wind speed of 6.70 m/s. Overall, this study provides a theoretical framework for the design of high-efficiency wind energy harvesters.