Broadband energy harvesting with mechanically coupled harvesters

This article investigates an array of pendulums as a potential broadband energy harvester. Closed form expression of the total power is analytically obtained. Effect of parameters on the total power harvested and on frequency band of the harvested power is accessed numerically. Finally experiments are carried out for arrays with two to five pendulums, which strongly supports the numerical observations. Different configurations are studied; (a) pendulums in the array are independent of each other, (b) pendulums are coupled using springs in between. The effect of mechanical grounding, where in the extreme pendulums are connected to the support through a spring, is also investigated. Observations show that array of coupled pendulums with mechanical grounding increased the bandwidth of harvesting frequency. The bandwidth and the total power harvested saturates with the number of pendulums.