Passive Multi-Source Energy Harvesting Schemes: Multiplicity of Piezoelectrics

Energy harvesting technologies present a solution to decreasing battery size and to the in-situ recharging of batteries in mobile devices or wireless sensor nodes. Combining multiple energy harvesters to power one system can increase the viability of potential designs as solutions for many applications. This work uses LTspice circuit simulations to examine passive circuit topologies for a multiplicity of piezoelectrics as a multisource energy harvesting solution. The simulation results show increases in the maximum instantaneous power seen on the storage capacitor for both a series and parallel circuit topology. There is also an increase in the available voltage level for the series topology. However, these increases in output power and voltage are sensitive to differences in the harvester outputs. Therefore, passive multi-source topologies present a viable solution for combining the energy from a multiplicity of piezoelectric harvesters.