Research on nonlinear isometric L-shaped cantilever beam type piezoelectric wind energy harvester based on magnetic coupling

Harvesting wind energy using piezoelectric materials is expected to be an alternative solution for powering wireless sensing networks. This paper proposed a nonlinear isometric L-shaped cantilever beam type piezoelectric wind energy harvester based on magnetic coupling (L-PWEH). The transducer consists of an array of equidistant L-shaped piezoelectric vibrators that are sealed inside the shell. It greatly improves the equivalent piezoelectric coefficient, robustness, and wind speed range for reliable operation. Theoretical and simulation analyses of the structural parameters related to the widening of the L-PWEH were performed. The prototype was built and the experimental system was constructed to verify the feasibility of the L-PWEH and the results of the analyses. Experiments have shown that increasing the magnetic force, additional springs, and the appropriate quantity of excitation magnets can effectively increase the output voltage and widen the wind speed range at high voltage output. When the wind speed is 16.35 m/s and the load resistance is 2 MΩ, the best output power of the piezoelectric vibrator is 142.3 µW. At this time, the height of the middle excitation magnet of the prototype is 12 mm, the number is 5, and the wire diameter of the additional spring is 1 mm. The prototype can successfully make the electronics work properly.