A Bistable Vibration Energy Harvester with Synchronized Extraction and Improved Broadband Operation through Self-Propelled Feedback

摘要

We have earlier presented a piezoelectric cantlever-based vibration energy harvester, which uses bistability from magnetic repulsion, and synchronized extraction circuits, to increase the harvested energy and the frequency range of operation. However, small amplitude excitations may not be able to overcome the magnetic repulsion, causing the cantilever to vibrate around one of the bistable positions with reduced amplitude. In this work, we present a mechanical method to increase the excitation amplitude range over which the harvester operation remains bistable, by spring-loading one of the previously fixed-position magnet creating the repulsive force, such that it can only move linearly, towards and away from the cantilever. As a result, as the magnet on the cantilever tip moves towards the spring-loaded magnet, the latter is pushed away, increasing the distance, hence reducing repulsion, and vice-versa. Thus, a sort of negative feedback is introduced, favoring bistable operation over larger excitation ranges.