Research On Coupling Mechanism Of Contactless Power Supply For Wireless Monitoring Node Of Water-lubricated Bearings

Water-lubricated bearings using water as the lubrication,which has the advantages of clean,stable,and low-cost.It is widely used in hydraulic machinery equipment,such as ships,naval vessels,and turbine.As one of the key parameters of water-lubricated bearings,the depth study on film pressure should be conducted for obtaining other bearing characteristics,such as bearing capacity and lubrication state.The wired method is mainly adopted in conventional film pressure measurement,which has great limitations.So,the wireless monitoring on film pressure has become a study hotspot.However,in film pressure wireless monitoring method of waterlubricated bearings,the wireless monitoring node rotating with shaft,the traditional power supply methods,such as battery-powered,slipring conduction and self-powered,are unable to ensure the safety,continuity,and stability of power supply for wireless monitoring node.Therefore,this thesis addresses the above issues with the following main research elements:(1)Based on the water-lubricated bearings wireless monitoring system and its node composition,this thesis proposed a contactless power supply method according to the structure of test bench and energy consumption of the node,and the design criteria have been given.After these,an electromagnetic coupler is designed and manufactured,which suitable for rotating condition.The proposed contactless power supply method and the electromagnetic coupler can ensure safe,stable and uninterrupted power supply to the node under rotating condition.(2)The equivalent circuit model and magnetic circuit model of coupler are established,and its mapping relationship between structural parameters and electrical parameters is obtained.Combined with the above theoretical model and finite element analysis,the influence of the number of magnetic cores,air gap,radial offset,and relative rotation of the primary and secondary sides on the performance of coupler is studied,which provides a theoretical basis for the design of this kind of rotary contactless power supply system and coupler.(3)In order to improve the transmission power and efficiency of system,starting from the basic resonance compensation circuit theory,and combined with the output characteristics of different compensation circuits,the compensation topology suitable for this topic is discussed and verified by the joint simulation of Maxwell and Simplorer software.Finally,the static and dynamic tests of coupler and resonance compensation circuit are carried out,which verifies the feasibility and stability of the coupler to supply power for the wireless monitoring node of water-lubricated bearings under rotating conditions.