A Design Tool for Electromagnetically-Transduced Vibration Energy Harvesters and Its Implications on the Limits of Natural Frequency Tuning

Abstract

Recent technological advancements in the field of microelectromechanical systems (MEMS) manufacturing has opened the door to the idea of using ubiquitous networks of wireless sensor nodes to achieve artificially intelligent control spaces; however, to be feasible, this technology demands an onboard power supply capable of lasting the expected lifetime of each sensor node. A possible solution to this demand exists in the field of vibration energy harvesting (VEH)—where power is scavenged from vibrations in the ambient environment. This thesis investigates the feasibility of varying the complex part of the load impedance of an electromagnetic VEH system to “tune” its primary natural frequency to match the frequency spectra of the surrounding environment. Additionally, a Matlab design tool simulating a shearing, single-phase, electromagnetic VEH system is presented. A VEH prototype was developed to test the tuning model, and validate the results of the Matlab design tool. The tuning models predicted that current materials available for the fabrication of a well-optimized electromagnetic VEH system are 3-4 orders of magnitude below what is required for tuning a measurable/useful amount—this result was corroborated in the VEH prototype. Additionally, the Matlab design tool was shown to be in good agreement with prototype results.