{"id":5716,"date":"2012-07-18T22:27:44","date_gmt":"2012-07-18T22:27:44","guid":{"rendered":"https:\/\/mtlsites.mit.edu\/annual_reports\/2012\/?p=5716"},"modified":"2012-07-18T22:27:44","modified_gmt":"2012-07-18T22:27:44","slug":"harvesting-energy-from-non-ideal-vibrations","status":"publish","type":"post","link":"https:\/\/mtlsites.mit.edu\/annual_reports\/2012\/harvesting-energy-from-non-ideal-vibrations\/","title":{"rendered":"Harvesting Energy from Non-ideal Vibrations"},"content":{"rendered":"

This project focuses on two vibration non-idealities that affect the performance of vibration energy harvesters [1<\/a>] <\/sup> [2<\/a>] <\/sup>. Most vibration energy-harvesting research focuses on harvesting from a fixed-frequency single-harmonic vibration. Correspondingly, most harvesters exhibit a single mechanical resonance that couples to the vibration. Real vibration spectra, however, often exhibit multiple and\/or non-stationary harmonics and random background vibrations. The inability to handle such non-ideal vibration sources has become a technological obstacle to the applicability of vibration energy harvesters. This work addresses the two major non-ideal vibration conditions illustrated in Figure 1: the non-stationary behavior of individual vibration harmonics, i.e., the slow drift of their frequencies over time; and the multi-harmonic character of the vibration spectra. It does so both theoretically and experimentally by modifying the behavior of a single-resonance vibration energy harvester through its electrical load [3<\/a>] <\/sup>.<\/p>\n

To support the experimental work, a vibration harvesting test bench is developed. The test bench is built around the V25W piezoelectric (PZT) energy harvester manufactured by Mide Technology. Figure 2 (a) shows the complete test bench; Figure 2 (b) shows the V25W PZT harvester mounted on a shaker table; and Figure 2 (c) shows the computer-based control and measurement system through which the test bed is excited and observed. It should be noted that the work pursued here uses a piezoelectric harvester out of convenience. The modifications studied here are applicable to vibration energy harvesters employing other energy conversion physics such as electric- and magnetic-based conversion.<\/p>\n\n\t\t