Attachable Magnetic-Piezoelectric Energy-Harvester Powered Wireless Temperature Sensor Nodes for Monitoring of High-Power Electrical Facilities

In this paper, we report attachable magnetic-piezoelectric energy harvester powered wireless temperature sensor nodes for monitoring of high-power electrical facilities. Each of sensor nodes consists of a magnetic-piezoelectric energy-harvester, power-management circuit, energy-storage capacitor, wireless transmitter, and temperature sensor. To harness different levels of magnetic-field energy induced by wires/conductors operated at different current levels in high-power electrical facilities, we design energy harvesters with different mechanisms specifically for above levels. These include a force-deflected cantilever energy harvester, force-deflected simple-beam energy harvester, and strain-mediated magnetoelectric (ME) energy harvester. The above energy harvesters powered sensor nodes are attached on an industrial standard copper bus-bar carrying different ultra-high currents to test their energy-harvesting and temperature-monitoring performance. The test results show that the maximum current-carrying capacity of the copper bus-bar for the cantilever-beam, simple-beam, and magnetoelectric energy harvesters are 266 A, >900 A, and >900 A, respectively. Based on this, the energy harvesting performance of the cantilever, simple-beam, and ME energy-harvesters powered wireless temperature sensor nodes are 966 μW at 260 A, 526 μW at 700 A, and 59.8 μW at 700 A, respectively, and the corresponding cycle time of wireless temperature sensing are 3.5 minutes, 6 minutes, and 99 minutes, respectively. According to these results, the sensor nodes not only successfully achieve temperature sensing/monitoring of ultra-high-current electrical facilities, but also provide total solutions for electrical facilities with different power/current specifications. These results will be important fundamentals toward wireless sensors network (internet of things) for temperature monitoring of high-power electrical facilities.