An annular tubular wearable piezoelectric-electromagnetic hybrid vibration energy harvester driven by multi magnetic beads

Wearable devices are widely applied because of the rapid development of semiconductor devices and integrated circuit technology. People hoped to enhance their senses through various wearable devices. However, the application is currently limited by the operating time of electrochemical batteries. This paper presents an annular tubular wearable piezoelectric-electromagnetic hybrid vibration energy harvester driven by multi magnetic beads for harvesting energy from the arm swing motion. The structure consists of a piezoelectric beam, magnetic beads and a set of coils. Specifically, piezoelectric energy harvesting (PEH) converts vibration energy into electrical energy by using a new macro-fiber composite (MFC). Magnetic beads and coils form an electromagnetic energy harvester (EMEH). Two energy harvesting units are coupled by magnetic beads. The magnetic beads can not only induce the coil to generate electrical energy, but also excite the piezoelectric beam. Two conversion mechanisms extract energy simultaneously through one excitation. Experimental results show that the device can harvest the vibration energy generated by human activity under different types of human motion, such as slow walking, fast walking and running. The integration between PEH and EMEH not only extends the operating bandwidth, but also makes it easy for ultra-low frequency energy harvesting. The prototype harvester that could power a number of portable electronic devices shows great potential.

Automated summary

This paper presents a novel wearable vibration energy harvester that combines piezoelectric and electromagnetic mechanisms to extract vibration energy, and achieves ultra-low frequency energy harvesting. The experimental results demonstrate that the device can effectively collect vibration energy generated from various human motions.