Research On Piezoelectric Vibration Energy Harvesting Induced By Surface Wind On Large Rotational Machinery

To monitor the running status of key rotating bodies(drum,wheel)using wireless sensor node is a new way to detect typical fault of lifting system,however,short life of sensor nodes is a bottleneck problem of the application of the method.In order to meet the requirements of powering and lowering the power consumption of sensor nodes placed on the mine hoist drum,this paper studied wind-induced vibration piezoelectric energy harvesting on large rotational machinery.This paper firstly studied the fixation modes and adjusting methods of ceramic piezoelectric patch through software simulations and experiments;then a new piezoelectric vibration energy harvesting induced by surface wind is designed and verified by experiments to power the nodes;finally,two new energy management schemes is proposed from the point of view of energy management and comparative experiments are conducted.The main work of this thesis is as follows:1 The basic theory of piezoelectric materials is fully explained for the aim to lay a solid foundation for future studies of piezoelectric patch.2 The power generation capacity of ceramic piezoelectric patch in two different fixation modes(cantilever fixation mode and simply supported beam fixation mode)is studied through softwares simulation and experiments and two ways(weight of mass block and length-width ratio)of adjusting the natural frequency of piezoelectric patch are studied as well.The results show that cantilever beam fixed mode is suitable for large rotary body surface wind vibration piezoelectric energy harvester.3 A new piezoelectric vibration energy harvesting induced by surface wind was designed based on the research results above and the working environment of mine hoist.Force analysis of the ceramic piezoelectric patch model was achieved based on the basic theory of the Carmen vortex and more importantly,the generated voltage and power under three different key parameters(ration speed,cylindrical obstacle's diameter,installation angle)are obtained.With the help of ANSYS software,force analysis of piezoelectric patch was made and the stress distribution piezoelectric patch was obtained in working condition.Besides,maximum stress with different speed and cylindrical obstacle diameter versus rotational speed was acquired.A wind-induced vibration piezoelectric energy harvesting experiment device was build according to the theoretical model and mine hoist drum movement parameters.Several experiments are conducted with theoretical analysis..The results show that the design of the energy collection device has a power output of about 1mW when the rotational speed of the rotor reaches 145r/min;adjusting the installation angle of device can increase the output power of the energy harvester more effectively than the diameter of the cylindrical barrier.4 The energy management requirements of the sensor nodes on the surface of large rotating body are analyzed;An active frequency-adjusting strategy based on signal amplitude detection and a passive frequency-adjusting strategy for large rotating body are proposed.The performances of two kinds of frequency-adjusting strategies are analyzed by contrast test;the results show that the two methods can achieve power management;when the transmission frequency is 50 Hz,the power consumption of the passive frequency-adjusting strategy is less than that of the active frequency-adjusting strategy.6.8%.