Comparing Linear and Essentially Nonlinear Vibration-Based Energy Harvesting

Self-contained long-lasting energy sources are rapidly increasing in importance as portable electronics and inaccessible devices such as wireless sensors are finding wider and more varied applications. However, in many circumstances replacing power supplies, such as conventional batteries, becomes impractical and the development of a self-renewing source of energy is paramount to the continued development of such devices. The ability to convert ambient mechanical energy to usable electrical energy fills these requirements and one aspect of current research seeks to increase the efficiency and performance of these energy harvesting systems. However, to achieve acceptable performance conventional vibration-based energy harvesting devices based on linear elements must be specifically tuned to match environmental conditions such as the frequency and amplitude of the external vibration. As the environmental conditions vary under ambient conditions the performance of these linear devices is dramatically decreased. The strategy to efficiently harvest energy from low-level, intermittent ambient vibration, proposed herein, relies on the unique properties of a particular class of strongly nonlinear vibrating systems that are referred to as “essentially” nonlinear.