To simplify the mechanical structure, decrease the overall system size of the 3-degree freedom axial-radial magnetic bearings and reduce the manufacturing costs as well as operating costs, an innovated AC-DC 3-degree ...To simplify the mechanical structure, decrease the overall system size of the 3-degree freedom axial-radial magnetic bearings and reduce the manufacturing costs as well as operating costs, an innovated AC-DC 3-degree freedom hybrid magnetic bearing is proposed, which is driven by a DC amplifier in axial direction and a 3-phase power converter in radial directions respectively, and the axial and radial bias magnetic fluxes are provided with a common radial polarized permanent magnet ring. The principle producing magnetic suspension forces is introduced. By using equivalent magnetic circuit method, the calculation formulas of magnetic suspension forces and the mathematics models of the system are deduced. Nonlinearities of suspension forces and cross coupling between different degree freedoms are studied further by calculating the suspension forces at different displacements and control currents to validate the feasibility of the mathematics model. Then based on the mathematics models of the bearing, a control method of this novel bearing is designed. Lastly, the methods on parameter design and calculations of the bearing are presented, and an applicable prototype is simulated to analyze the magnetic path by using finite element analysis. The theory analysis and simulation results have shown that this magnetic bearing incorporates the merits of 3-phase AC drive, permanent magnet flux biased and axial-radial combined control, and reduces overall system size and has higher efficiency and lower cost, This innovated magnetic bearing has a wide application in super-speed and super-precision numerical control machine tools, bearingless motors, high-speed flywheels, satellites, etc.展开更多
This paper presents a methodology for analytical calculation and computational simulation using the finite element method for piezoresistive graphite sensor element on flexible polymer substrate,A4 paper.The computer ...This paper presents a methodology for analytical calculation and computational simulation using the finite element method for piezoresistive graphite sensor element on flexible polymer substrate,A4 paper.The computer simulation aims to find the region of greatest mechanical tension and deflection of the circular diaphragm set in the circumference edges.The steps for simulation are geometry definition,mesh generation,inclusion of material physical properties and simulation execution.The mathematical modeling of maximum mechanical stress and deflection is described analytically and computationally.The analytical calculations were compared with the computer simulation and presented a relative percentage error of 3.38%for the maximum deflection.The results show that the piezoresistor should be positioned at the edges of the circular diaphragm to take advantage of maximum mechanical stress by defining the best location for graphite film deposition for sensor device designs and fabrications.展开更多
基金This project is supported by National Natural Science Foundation of China(No.50575099).
文摘To simplify the mechanical structure, decrease the overall system size of the 3-degree freedom axial-radial magnetic bearings and reduce the manufacturing costs as well as operating costs, an innovated AC-DC 3-degree freedom hybrid magnetic bearing is proposed, which is driven by a DC amplifier in axial direction and a 3-phase power converter in radial directions respectively, and the axial and radial bias magnetic fluxes are provided with a common radial polarized permanent magnet ring. The principle producing magnetic suspension forces is introduced. By using equivalent magnetic circuit method, the calculation formulas of magnetic suspension forces and the mathematics models of the system are deduced. Nonlinearities of suspension forces and cross coupling between different degree freedoms are studied further by calculating the suspension forces at different displacements and control currents to validate the feasibility of the mathematics model. Then based on the mathematics models of the bearing, a control method of this novel bearing is designed. Lastly, the methods on parameter design and calculations of the bearing are presented, and an applicable prototype is simulated to analyze the magnetic path by using finite element analysis. The theory analysis and simulation results have shown that this magnetic bearing incorporates the merits of 3-phase AC drive, permanent magnet flux biased and axial-radial combined control, and reduces overall system size and has higher efficiency and lower cost, This innovated magnetic bearing has a wide application in super-speed and super-precision numerical control machine tools, bearingless motors, high-speed flywheels, satellites, etc.
文摘This paper presents a methodology for analytical calculation and computational simulation using the finite element method for piezoresistive graphite sensor element on flexible polymer substrate,A4 paper.The computer simulation aims to find the region of greatest mechanical tension and deflection of the circular diaphragm set in the circumference edges.The steps for simulation are geometry definition,mesh generation,inclusion of material physical properties and simulation execution.The mathematical modeling of maximum mechanical stress and deflection is described analytically and computationally.The analytical calculations were compared with the computer simulation and presented a relative percentage error of 3.38%for the maximum deflection.The results show that the piezoresistor should be positioned at the edges of the circular diaphragm to take advantage of maximum mechanical stress by defining the best location for graphite film deposition for sensor device designs and fabrications.
