Study on Application of Piezoelectric Vibration Energy Harvesters for Powering of Wireless Sensor Nodes in Large Rotary Machine Diagnostic Systems
B. Pekoslawski, P. Pietrzak, M. Makowski, L. Szafoni, A. Napieralski
Technical University of Lodz, PL
Keywords: energy harvesting, Vibration Energy Harvester, piezogenerator, autonomous power supply, Wireless Sensor Network, sensor node powering, large rotary machine, turbogenerator, condition monitoring
Abstract:A condition monitoring of large rotary machines such as turbogenerators in power plants can be more convenient and less expensive when using a distributed measurement system with wireless sensor nodes. A battery-based powering of these sensor nodes has, however, several limitations. The authors propose an alternative solution applying small-size piezoelectric generators, in which energy of machine mechanical vibrations is harvested and converted to electric energy. Experimental studies were conducted for a cantilever–beam bender piezogenerator. A maximization of generated electric power was achieved by matching load impedance to piezoelectric element output impedance and designing suitable weighting mass for mechanical resonance. Diodes in bridge rectifier were carefully selected to minimize power-processing losses. Various DC voltage regulators including switching ones were also studied. The operation of the piezoelectric element and the weighting mass setup was investigated in real conditions on a turbogenerator. Generated power levels were compared for three vibration directions and for various locations on the turbogenerator stator. The results of the studies can be useful for a future work on micromachined piezoelectric Vibration Energy Harvesters for large rotary machine condition-monitoring systems. Some other issues, such as piezoelectric material degradation and mounting to vibrating machine surface, are also discussed.