Research On Efficient Energy Harvesting And Self-powered Wireless Sensor Node Piezoelectric Energy Harvester

With the continuous development of sensor network and Internet of Things(IOT),the power supply of sensor nodes that constitute these network has also drawn more and more attention.Especially in places with limited power supply such as bridges,oil pipelines,and road fences,etc.,how to harvest the energy in the environment to maintain the operation of the sensor nodes has become a hot research topic at home and abroad recently.Based on this consideration,a self-powered wireless sensor node capable of monitoring vibration events,improving the energy harvesting efficiency and sending alarm information using environmental vibration energy is designed based on the full research of piezoelectric vibration energy harvester,and realize the network of this sensor nodeFirst of all,this paper takes the multi-physics coupled energy harvester as the research object,and designs an impedance matching interface circuit that can realize efficient energy capture based on theoretical model research and analysis of its electrical characteristics.Then a self-powered wireless sensor node based on the interface circuit is constructed.The node is composed of energy harvester,impedance matching interface circuit,power management module and RF transmission module.Finally,the node was used to build a self-powered wireless sensor monitoring network.The network was based on RF communication in the 433 MHz frequency band and GSM communication,and realized monitoring and alarming of vibration events of each node.Experiments show that the proposed impedance matching interface circuit improves the energy harvesting power by about 48.1%-55.7%compared to the standard piezoelectric energy harvesting interface circuit under the vibration excitation with a frequency of 20-40 Hz and an acceleration amplitude of 5.5 g.The proposed self-powered wireless sensor node can start and transmit alarm information in 75.8 s under the vibration excitation with a frequency of 40 Hz and an acceleration amplitude of 5.5 g,and it can work continuously at an average time intervals of 31.1s.Compared with self-powered wireless sensor node using standard energy harvesting interface circuit,the response time is reduced by 33%.The transmission power of the RF module is up to 10 dBm,and the transmission distance can reach 1.31 km.The proposed sensor node can be widely used in the safety monitoring of unattended key targets such as road fences and oil pipelines,and has wide application value.