Method And Experimental Study For Rotary Energy Harvesting For Wireless Monitoring Of Water Film Pressure

Water film pressure is one of the important parameters to characterize the lubrication film characteristics of water-lubricated bearings.It is of great significance to obtain the empirical data of water film pressure through the method of experimental testing for solving the problems related to lubrication theory.With the progress of science and technology,the method of water film pressure test using wireless sensing technology has made great progress,which is hot spot and frontier of research.However,in the application of the water film pressure wireless sensing test method,because the wireless node is installed on the rotating shaft to rotate with the shaft at high speed,is not a common static application environment,therefore,its power supply is a major problem.Battery power is usually used to power wireless nodes,but its energy is limited,and if the energy runs out,it will greatly affect the test process;In addition,the replacement of the battery needs frequent shutdown,very inconvenient.Aiming at the special application environment of the wireless monitoring node of water film pressure,this thesis proposes a method of rotating energy collection and power supply and designs an energy collection and storage device,which solves the problem of continuous online power supply of the wireless monitoring node of water film pressure by combining the scheme of permanent magnet generator and lithium battery.At the same time,the rotational energy harvesting method can be extended to other wireless nodes in the process of rotating motion.The main research work of this thesis is as follows:(1)The PMSG model was introduced to establish the three-phase permanent magnet alternator efficiency mathematical model,and the physical model of the generator was established with the application of Ansoft software.Based on the actual parameters of the permanent magnet generator,the real working conditions were simulated,the relationship curve between the speed and the energy conversion efficiency was obtained,and the relationship between the speed and the efficiency was analyzed.The structure and energy consumption of water film pressure wireless monitoring nodes were analyzed.Based on this,the energy consumption model of nodes was established,and the energy consumption in the nodes and in the process of data transmission were obtained.The power flow model of the water film pressure testing system was established to analyze the energy collection efficiency.(2)The energy collecting device is designed,including rectifier circuit,voltage regulator circuit,charge management circuit and lithium battery.Circuit simulation and analysis are carried out by using Multism software.In order to reduce the energy consumption of energy collection circuit and improve the efficiency of energy collection,low power components and chips are used in the circuit design.The rectifying circuit adopts three-phase bridge type,the voltage stabilizing circuit adopts3554 AM,and the charging management circuit chip adopts VAS5175 A.The results show that the designed energy harvesting circuit is feasible and correct,and can meet the power supply requirements of water film pressure wireless nodes.(3)The rotating energy collection test of the water film pressure wireless monitoring node was carried out,and the efficiency of the water film pressure testing system was analyzed.In the test,the voltage,current and power changes of each module of the energy collecting device in the charging process at different speeds were tested and tested by means of synchronous measurement of multiple groups of data,and the three stages of constant current,constant voltage and termination in the charging process were deeply analyzed.Finally,the energy harvesting efficiency and the energy conversion efficiency of the water film pressure testing system under different rotating speeds are studied and compared with the theoretical results.The results show that the speed is one of the main factors affecting the efficiency of the water film pressure wireless measurement system,and the higher the speed,the greater the efficiency of the system.