A Theoretical Description of a Multi-source Energy Harvester

Abstract

By harvesting energy from more than one source, it is possible to improve the power output from an energy harvester. In this paper we present an analysis that allows us to find a bound on the maximum power absorbed by a harvester from multiple sources. This is based on an extension of the analysis that was previously used to derive a power-bound for a single-source mechanical energy harvester driven by stochastic vibration. Firstly, a single-source power-bound is derived for a system with thermo-electrical coupling, driven by stochastic time-varying temperature gradients. This power-bound is verified using numerical simulations carried out using MATLAB. This analysis is then extended to a system with thermo-electro-mechanical coupling, driven by both fluctuating temperature gradients and mechanical vibration. The resulting power-bound is the sum of the theoretical bounds on the maximum power absorbed by the thermal system and mechanical system alone. As this power-bound is greater than that for a single-source system, it demonstrates that a system that harvests energy from multiple sources has the potential to achieve a greater power output than a system that only harvests energy from a single source.