Piezoelectric energy harvester for pacemaker application: a comparative study

Abstract

This study proposes the cantilever design of piezoelectric energy harvester scavenging energy from blood pressure variation in cardiac cycle. The harvester could be a perennial source of power for a typical pacemaker. The concept of three cm long and 72 mu m thin cantilever based energy harvester having natural frequency close to that of heartbeat has been proposed. Considering a huge difference between shear (d(15)) and transverse (d(31)) piezoelectric coefficient the harvester was operated in two different modes. A number of materials (single and polycrystalline ceramics) along with Pb[ZrxTi1_(x)]O-3 (PZT-5A) were operated in transverse and shear modes. The maximum open circuit voltage found for all cases was similar to 6 V which was yielded by Pb(Zn1/3Nb2/3)O-3-(6-7)% PbTiO3 (PZNPT) when operating in shear mode. Further, the optimum resistance was calculated for all the materials under study operating in d(15) and d(31) modes for a wide frequency range. It was found that the maximum power among all materials under study was given by PZN-PT which is similar to 13 mu W while operating in shear mode. Such high magnitude of power harvested is due to its giant d(15) which is 6000 pC N-1 and is sufficient to power a typical pacemaker.