Piezoelectric energy harvester for pacemaker application: A comparative study

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 μm thin cantilever based energy harvester having natural frequency close to that of heartbeat has been proposed. Considering a huge difference between shear (d₁₅) and transverse (d₃₁) piezoelectric coefficient the harvester was operated in two different modes. A number of materials (single and polycrystalline ceramics) along with Pb[Zr_xTi_1-x]O₃ (PZT-5A) were operated in transverse and shear modes. The maximum open circuit voltage found for all cases was ∼6 V which was yielded by Pb(Zn_1/3Nb_2/3)O₃-(6-7)% PbTiO₃ (PZN-PT) when operating in shear mode. Further, the optimum resistance was calculated for all the materials under study operating in d₁₅ and d₃₁ 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 ∼13 μW while operating in shear mode. Such high magnitude of power harvested is due to its giant d₁₅ which is 6000 pC N^-1 and is sufficient to power a typical pacemaker.