A Control Approach for Broadening the Operating Frequency Range of a Bridge Vibration Energy Harvester

Remote bridge condition monitoring can be accomplished using sensors equipped with transmitters. This allows for timely detection of structural degradation and thereby increases safety. These sensors require a more permanent power source than batteries to enable operation without costly periodic maintenance. Since bridges exhibit structural vibration, electromagnetic vibration energy harvesting is a viable power source candidate. Unfortunately conventional electromagnetic vibration energy harvesters (VEHs) operate efficiently only at their natural frequency. Since a single bridge will vibrate differently, depending on its traffic conditions, the following work proposes a method for augmenting the excitation frequency bandwidth for electromagnetic VEHs, thereby enabling them to be feasible power supplies for bridge condition monitoring. Specifically, the paper provides experimental results showing the effectiveness of the proposed method in inducing resonance type behavior in an electromagnetic VEH at excitation frequencies that otherwise produce little to no motion in the harvester.