Performance Evaluation of Multi-tier Energy Harvesters Using Macro-fiber Composite Patches

This study presents the performance evaluation of a vibration-based energy harvester using macro-fiber composite (MFC) elements, which can harvest power from environmental or ambient vibration and shock. An innovative multi-tier energy harvester (MTEH), comprised of a small number of vibrating beam elements with same fundamental frequencies, is developed in this study to overcome the harvested power limitations of single-tier energy harvesters (STEHs) with only a single vibrating beam element. First, the governing equations of motion of an MTEH were theoretically obtained for series and parallel connections of pairs of MFC patches on each tier surface. Based on the theoretical model, a vibration-based MTEH, having three tiers with MFC patches adhered to the bottom and top of each tier surface, was designed and fabricated. MTEH performance, which included generated voltage, current, and power, was experimentally and theoretically evaluated in the frequency domain and compared with that of a similar STEH.