Due to low viscosity of seawater,it is difficult to form a seawater-lubricated film.It is easy to cause the overload and burning phenomenon of seawater-lubrication sliding bearing,and then the operation stability and ...Due to low viscosity of seawater,it is difficult to form a seawater-lubricated film.It is easy to cause the overload and burning phenomenon of seawater-lubrication sliding bearing,and then the operation stability and service life can be shortened seriously.Therefore,the paper introduces an electromagnetic suspension theory into the seawater lubricated sliding bearing.Then a novel magnetic-liquid double suspension bearing can be formed,which can enhance bearing capacity and stiffness greatly.Firstly,the structural characteristics,support-adjustment mechanism of magnetic-liquid double suspension bearing is analyzed.Secondly,based on force balance equation,electromagnetic equation and flow equation,the transfer functions of single DOF bearing system of magnetic-liquid double suspension bearing under constant-flow supply model are deduced.Then bearing capacity,static stiffness and total power loss are selected as static performance indexes.The influence rule of operaton and structural parameters on the static performance of single DOF bearing system will be analyzed.The results show that bearing capacity decreases with the increase of liquid film thickness and width of edge seals,bias current and coil turns decrease.Static stiffness decreases with the increase of liquid film thickness,edge seals width,bias current and coil turns.Total power loss decreases with the increase of liquid film thickness,edge seals width,bias current and coil turns decrease.And static performance indexes can not be affected by liquid viscosity.The proposed research provides some theoretical and experimental basis for the parameter design of magnetic-liquid double suspension bearing.展开更多
针对传统动态电压恢复器(dynamic voltage restorer,DVR)拓扑结构直流侧电压等级高,逆变单元输出电压波形畸变率大及其损耗亦较高的问题,依据开放式绕组原理提出新型DVR拓扑结构。研究了新型DVR拓扑实现低谐波畸变率和低直流侧电压幅值...针对传统动态电压恢复器(dynamic voltage restorer,DVR)拓扑结构直流侧电压等级高,逆变单元输出电压波形畸变率大及其损耗亦较高的问题,依据开放式绕组原理提出新型DVR拓扑结构。研究了新型DVR拓扑实现低谐波畸变率和低直流侧电压幅值的方法;建立了新型DVR等效电路模型,并给出新型DVR拓扑的控制策略。同时分析对比了新型DVR与传统DVR拓扑的功耗,结果表明新型DVR功耗较低。最后,在MATLAB/SIMULINK平台搭建仿真模型,仿真结果证明所提出的DVR拓扑结构性能优越,补偿精度高。展开更多
基金Support by the National Natural Science Foundation of China(No.51705445)the Open Project Funding of Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Controlthe Open Project Funding of Jiangsu Provincial Key Laboratory of Advanced Manufacture and Process for Marine Mechanical Equipment
文摘Due to low viscosity of seawater,it is difficult to form a seawater-lubricated film.It is easy to cause the overload and burning phenomenon of seawater-lubrication sliding bearing,and then the operation stability and service life can be shortened seriously.Therefore,the paper introduces an electromagnetic suspension theory into the seawater lubricated sliding bearing.Then a novel magnetic-liquid double suspension bearing can be formed,which can enhance bearing capacity and stiffness greatly.Firstly,the structural characteristics,support-adjustment mechanism of magnetic-liquid double suspension bearing is analyzed.Secondly,based on force balance equation,electromagnetic equation and flow equation,the transfer functions of single DOF bearing system of magnetic-liquid double suspension bearing under constant-flow supply model are deduced.Then bearing capacity,static stiffness and total power loss are selected as static performance indexes.The influence rule of operaton and structural parameters on the static performance of single DOF bearing system will be analyzed.The results show that bearing capacity decreases with the increase of liquid film thickness and width of edge seals,bias current and coil turns decrease.Static stiffness decreases with the increase of liquid film thickness,edge seals width,bias current and coil turns.Total power loss decreases with the increase of liquid film thickness,edge seals width,bias current and coil turns decrease.And static performance indexes can not be affected by liquid viscosity.The proposed research provides some theoretical and experimental basis for the parameter design of magnetic-liquid double suspension bearing.
文摘针对传统动态电压恢复器(dynamic voltage restorer,DVR)拓扑结构直流侧电压等级高,逆变单元输出电压波形畸变率大及其损耗亦较高的问题,依据开放式绕组原理提出新型DVR拓扑结构。研究了新型DVR拓扑实现低谐波畸变率和低直流侧电压幅值的方法;建立了新型DVR等效电路模型,并给出新型DVR拓扑的控制策略。同时分析对比了新型DVR与传统DVR拓扑的功耗,结果表明新型DVR功耗较低。最后,在MATLAB/SIMULINK平台搭建仿真模型,仿真结果证明所提出的DVR拓扑结构性能优越,补偿精度高。
