Design of a multi-array piezoelectric energy harvester for a wireless switch

Abstract

We propose a new soft-push-type piezoelectric energy harvester (PEH), a multi-array system for which we developed a self-powered wireless switch that uses infrared communication. Our results show its adequacy as a energy source in wireless switch in comparison with cantilever- and impact-type harvesters. The disadvantages of using PEHs in wireless switches is its large size and complicated mechanical system, which we overcame by designing a soft-push-type PEH. The technique presented reduces the large phase difference problem in two parallel connected piezoelectric beams to 3%. Based on this result, our circuit requires only single rectifier as compared to two rectifiers for each piezoelectric cantilever beam, thus reducing the size of the circuit board and production cost. Proposed PEH works at non-resonance and its resistive impedance matching is reduced to half, to 250 k Omega by connecting the two beams in parallel and to achieve a power output of 4 mW. This soft-push-type harvester generated 324 mu J of energy with one push when connected to a wireless transmitter circuit.