Much of the work on improving energy harvesting systems currently focuses on tasks beyond geometric optimization and has shifted to using complex feedback control circuitry. While the specific technique and effectiveness of the circuits have varied, an important goal is still out of reach for many desired applications: to produce sufficient and sustained power. This is due in part to the power requirements of the control circuits themselves. One method for increasing the robustness and versatility of energy harvesting systems which has started to receive some attention would be to utilize multiple energy sources simultaneously. If some or all of the present energy sources were harvested, the amount of constant power which could be provided to the system electronics would increase dramatically. This work examines two passive circuit topologies, parallel and series, for combining multiple piezoelectric energy harvesters onto a single storage capacitor using an LTspice simulation. The issue of the relative phase between the two piezoelectric signals is explored to show that the advantages of both configurations are significantly affected by increased relative phase values.

Date Published: 27 April 2011
PDF: 9 pages
Proc. SPIE 7977, Active and Passive Smart Structures and Integrated Systems 2011, 79770J (27 April 2011); doi: 10.1117/12.880674

Published in SPIE Proceedings Vol. 7977:
Active and Passive Smart Structures and Integrated Systems 2011
Mehrdad N. Ghasemi-Nejhad, Editor(s)