Magnetic Bearing Magnetic Field Sensing And Measurement Systembased On Fiber Bragg Grating

Magnetic bearings electromagnetic field analysis is an important component ofthe magnetic bearing research. Because of the complexity of the magnetic bearingsand specificity of its structure, the measured magnetic field in the air gap is difficultto achieve. Based on the unique advantages of fiber gratings, this paper proposes acombination of magnetostrictive components and fiber grating, design a magneticfield sensor to achieve the actual measurement of the magnetic bearing of theelectromagnetic field, and test magnetic field sensor performance generated by thecoil of U-shaped magnetic field.In this paper, the object is radial magnetic bearings (using NNSS polearrangement), considering three working states: the rotor suspension, the rotorrotation, the coil of loading different frequencies dynamic currents. Firstly, it analyzesthe electromagnetic field distribution in the air gap magnetic bearings. So that, itdraws the scale and installation location of the designed magnetic field sensor. Then,it analyzes the sensing principles of the magnetic field sensor, including the sensingprinciple of fiber Bragg grating and the sensing principle of the magnetostrictivecomponents. Finally, it tests the performance of the designed magnetic field sensor.The core work of this paper is designing the magnetic field sensor and testing itsstatic and dynamic performance. In the designing of the magnetic field sensor, itmainly discusses the size of magnetostrictive components、the paste method of themagnetostrictive element and fiber Bragg grating and installation location ofmagnetic field sensor. In the section of testing its performance, the coil of U-shaped isdesigned to simulate the magnetic field in the air gap magnetic bearings, includingthe design of its coil turns and air gap. In static experiments, two key work must bedone:(1) the compare of theoretical and measured values of relationship betweencurrent and magnetic field.(2)the relationship between the magnetic flux density anda wavelength shift. In the dynamic experiments, the main work is: while the coil ofU-shaped is loaded the same amplitudes but different frequencies dynamic current,we can draw the variation of the wavelength shift under the different frequencies dynamic current. Due to signal interference, the FFT analysis is must be done.Through data analysis and processing, we can see that the magnetic field sensingdevice designed FBG has good sensing performance and can be used to measure themagnetic bearing air gap magnetic field.