An E-shape broadband piezoelectric energy harvester induced by magnets

We describe in this work a broadband magnetic E-shape piezoelectric energy harvester with wide frequency bandwidth. We develop first a nonlinear electromechanical model of the harvester based on the Hamilton variation principle that simulates the effect of the nonlinear magnetic restoring force at different spacing distances. The model is used to identify the distances existing between two different magnets that enable the system to perform with a specific nonlinearity. The performance of the E-shape piezoelectric energy harvester is also investigated through experiments, with E-shape energy harvesters at different spacing distances tested under several base acceleration excitations. We observe that the frequency domain output voltage of the system shows a general excellent controllable performance, with a widening of the frequency bandwidth. The half-power bandwidth of the linear energy harvester for a distance of 25 mm is 0.8 Hz only, which can be expanded to 2.67 Hz for the larger distance of 11 mm between magnets. The energy harvester presented in this work shows promising performances for broad-spectrum vibration excitations compared to conventional cantilever piezoelectric energy harvester systems with a tip mass.