本文旨在研發徑向間隙感測器作為間隙訊號回授及控制使用，並應用於磁軸承控制系統及故障偵測使用。本文提出電感型感測器的線性差動變壓器的結構，此方法可提高感測器量測間隙範圍及線性度，降低成本。此裝置含有兩放置相差機械角180度位置，且具有差動的結構。利用線圈的不同感應電勢電壓信號以偵測軸承的徑向位移偏差。硬體電路採用激磁弦波電壓源產生電路、分壓電路、精密全波整流、差動放大電路、位準調整電路，及數位控制器的類比-數位轉換器(ADC)讀取並做後續處理。系統採用數位信號處理器TMS320F280049為偵測系統的核心，利用內部12位元的類比-數位轉換器，可將偵測線圈之類比感測信號轉換為數位信號。間隙位置偵測之軟體編寫皆以C語言完成，並以Labview 顯示間隙數值和警示燈顯示目前軸承是否在正常工作區。本文將以PSIM 軟體模擬硬體電路架構，以驗證本裝置之可行性。徑向偏移量設定範圍為-2mm~2mm，最大誤差量為2%，平均誤差量為1%。

The aim of this thesis is to develop a radial gap sensor for the purpose of feedback and control of gap signals, to be used in magnetic bearing control systems and fault detection. The thesis proposes a linear variable differential transformer structure for an inductive type sensor, which improves the measurement range and linearity of the sensor while reducingcost. The device consists of two mechanically angularly offset positions and has a differential structure. By using the voltage signals induced by different coil potentials, the radial misalignment of the bearing can be
detected: The hardware circuit includes a sinusoidal excitation voltage source, voltage division circuit, precision full-wave rectification,differential amplification circuit, reference adjustment circuit and an analogue-to-digital converter (ADC) in the digital controller for signal reading and subsequent processing. The system uses a digital signal processor, specifically the TMS320F280049, as the core of the detection system, with an internal 12-bit analogue-to-digital converter to convert the analogue sensing signals from the detection coils into digital signals. The software programming for displacement detection is implemented in the C language, and LabVIEW is used to display the displacement and indicate whether the bearing has deviated into the fault zone. The hardware circuit architecture is simulated using PSIM software to verify the feasibility of the device. The radial offset adjustment range is -2mm to 2mm, with a maximum error of 2% and an average error of 1%.

[1]L. Xi'nan, W. Fengxiang, and W. Baoguo, "Application of Eddy-Current Sensor for Air Gap Detection in Magnetic Suspension Motors," in ICEMS'2001. Proceedings of the Fifth International Conference on Electrical Machines and Systems (IEEE Cat. No. 01EX501), 2001, vol. 1: IEEE, pp. 326-329.
[2]M. Sun, J. Zhou, B. Dong, and S. Zheng, "Driver Circuit Improvement of Eddy Current Sensor in Displacement Measurement of High-Speed Rotor," IEEE Sensors Journal, vol. 21, no. 6, pp. 7776-7783, 2020.
[3]W. Liu et al., "Measurement of Three-Dimensional Information by Single Eddy Current Displacement Sensor," IEEE Sensors Journal, vol. 19, no. 9, pp. 3543-3552, 2019.
[4]M. Zong, L. Ba, and F. Wang, "Study on Novel Measuring Method for Rotor Axial Displacement with Displacement Sensor Fixed on Radial Direction in Magnetic Bearing," in 2008 International Conference on Electrical Machines and Systems, 2008: IEEE, pp. 726-729.
[5]C. Rui, L. Hongwei, and T. Jing, "Structure Design and Simulation Analysis of Inductive Displacement Sensor," in 2018 13th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2018: IEEE, pp. 1620-1626.
[6]Y. Yu, H. Li, K. Xue, D. Liu, and G. Gao, "Temperature Invariant Phenomenon in Dual Coil Eddy Current Displacement Sensor: Investigation, Verification and Application," IEEE Sensors Journal, vol. 19, no. 21, pp. 9680-9687, 2019.
[7]S. Ding and Y. Yang, "Realization of Numeral Eddy Current Sensor Modeling," in 2012 Fifth International Symposium on Computational Intelligence and Design, 2012, vol. 1: IEEE, pp. 527-530.
[8]K. Wang, L. Zhang, S. Zheng, J. Zhou, and X. Liu, "Analysis and Experiment of Self-Differential Eddy-Current Sensor for High-Speed Magnetic Suspension Electric Machine," IEEE Transactions on Industry Applications, vol. 55, no. 3, pp. 2538-2547, 2018.
[9]Y. Yating, D. Pingan, and W. Zhenwei, "Study on The Electromagnetic Properties of Eddy Current Sensor," in IEEE International Conference Mechatronics and Automation, 2005, 2005, vol. 4: IEEE, pp. 1970-1975.
[10]Y. Tuo, Y. Yating, D. Pingan, and L. Yongchun, "The Development of Displacement Eddy Current Sensor Independent of Sample Electromagnetic Properties," in 2010 International Conference on Mechanical and Electrical Technology, 2010: IEEE, pp. 453-457.
[11]G. F. Zhao, J. Ying, L. Wu, and Z. H. Feng, "Eddy Current Displacement Sensor with Ultrahigh Resolution Obtained Through the Noise Suppression of Excitation Voltage," Sensors and Actuators A: Physical, vol. 299, p. 111622, 2019.
[12]H. Wang, W. Li, and Z. Feng, "A Compact and High-Performance Eddy-Current Sensor Based on Meander-Spiral Coil," IEEE Transactions on Magnetics, vol. 51, no. 9, pp. 1-6, 2015.
[13]P. Ragunathan and E. Logashanmugam, "Design and Fabrication of Low Cost Eddy Current Sensor for Position Control Applications," Indian Journal of Science and Technology, vol. 9, p. 42, 2016.
[14]Z. Gang, J. Dede, R. Juan, Y. Qingzhen, Z. Xue, and W. Chunlan, "Integrated Design and Research of Active Magnetic Bearing-Sensor," in 2011 Third International Conference on Measuring Technology and Mechatronics Automation, 2011, vol. 2: IEEE, pp. 433-436.
[15]K. Wang, L. Zhang, Y. Le, S. Zheng, B. Han, and Y. Jiang, "Optimized Differential Self-Inductance Displacement Sensor for Magnetic Bearings: Design, Analysis and Experiment," IEEE Sensors Journal, vol. 17, no. 14, pp. 4378-4387, 2017.
[16]K. Banerjee, B. Dam, and K. Majumdar, "A Novel FPGA-Based LVDT Signal Conditioner," in 2013 IEEE International Symposium on Industrial Electronics, 2013: IEEE, pp. 1-6.
[17]G. Chen, B. Zhang, P. Liu, and H. Ding, "An Adaptive Analog Circuit for LVDT’s Nanometer Measurement without Losing Sensitivity and range," IEEE Sensors Journal, vol. 15, no. 4, pp. 2248-2254, 2014.
[18]M. Zong, L. Ba, and F. Wang, "Study on Novel Measuring Method for Rotor Axial Displacement with Displacement Sensor Fixed on Radial Direction in Magnetic Bearing," in 2008 International Conference on Electrical Machines and Systems, 2008: IEEE, pp. 726-729.
[19]M. Recheis, J. Nicolics, H. Wegleiter, B. Schweighofer, and P. Fulmek, "Evaluation of Inductive Displacement Sensors for a Basic Active Magnetic Bearing Test Rig," in Proceedings of the 2011 34th International Spring Seminar on Electronics Technology (ISSE), 2011: IEEE, pp. 626-631.
[20]C. Rui, L. Hongwei, and T. Jing, "Structure Design and Simulation Analysis of Inductive Displacement Sensor," in 2018 13th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2018: IEEE, pp. 1620-1626.
[21]T. Matsuzaki, M. Takemoto, S. Ogasawara, S. Ota, K. Oi, and D. Matsuhashi, "Novel Structure of Three-Axis Active-Control-Type Magnetic Bearing for Reducing Rotor Iron Loss," IEEE Transactions on Magnetics, vol. 52, no. 7, pp. 1-4, 2016.
[22]N. Tsukada, T. Onaka, J. Asama, A. Chiba, and T. Fukao, "Novel Coil Arrangement of an Integrated Displacement Sensor with Reduced Influence of Suspension Fluxes for a Wide Gap Bearingless Motor," IEEE Transactions on Industry Applications, vol. 46, no. 6, pp. 2304-2310, 2010.
[23]A. J. Fleming, "A Review of Nanometer Resolution Position Sensors: Operation and Performance," Sensors and Actuators A: Physical, vol. 190, pp. 106-126, 2013.
[24]Z. Wenyue, Y. Junyue, and G. Yanjun, "A High Accuracy Displacement Detection Method for Magnetic Bearing," in 2010 International Conference on Electrical and Control Engineering, 2010: IEEE, pp. 66-68.
[25]L. Pecly, R. Schindeler, D. Cleveland, and K. Hashtrudi-Zaad, "High-Precision Resolver-to-Velocity Converter," IEEE Transactions on Instrumentation and Measurement, vol. 66, no. 11, pp. 2917-2928, 2017.
[26]H. Wu, F. Zhang, T. Liu, F. Meng, J. Li, and X. Qu, "Absolute Distance Measurement Using Optical Sampling by Cavity Tuning," IEEE Photonics Technology Letters, vol. 28, no. 12, pp. 1275-1278, 2016.
[27]R. Dhawan, N. Kawade, and B. Dikshit, "Design and Performance of a Laser-Based Compact Position Sensor for Long Standoff Distance," IEEE Sensors Journal, vol. 18, no. 16, pp. 6557-6562, 2018.
[28]J. Mesa, D. B. Vasquez, J. V. Aguirre, and J. S. B. Valencia, "Sensor Fusion for Distance Estimation Under Disturbance with Reflective Optical Sensors Using Multi Layer Perceptron (MLP)," IEEE Latin America Transactions, vol. 17, no. 09, pp. 1418-1423, 2019.
[29]Z. Wan, H. Luo, and L. Huang, "Design of Ultrasonic Distance Measurement System for Distance Benchmark Based on STM32," in 2022 6th Asian Conference on Artificial Intelligence Technology (ACAIT), 2022: IEEE, pp. 1-7.
[30]N. A. Singh and M. Borschbach, "Effect of External Factors on Accuracy of Distance Measurement Using Ultrasonic Sensors," in 2017 International Conference on Signals and Systems (ICSigSys), 2017: IEEE, pp. 266-271.
[31]Y. Hashimoto, A. Nakai, K. Matsumoto, and I. Shimoyama, "Single Pulse Proximal Distance Sensor with Thermoacoustic Transmitter," in TRANSDUCERS 2009-2009 International Solid-State Sensors, Actuators and Microsystems Conference, 2009: IEEE, pp. 1182-1185.
[32]I. O. Zaitsev, A. S. Levytskyi, and B. A. Kromplyas, "Capacitive Distance Sensor with Coplanar Electrodes for Large Turbogenerator Core Clamping System," in 2019 IEEE 39th International Conference on Electronics and Nanotechnology (ELNANO), 2019: IEEE, pp. 644-647.
[33]Y. Wu and T. Huang, "Design of High Precision Capacitance Displacement Sensor," in 2018 IEEE 3rd Advanced Information Technology, Electronic and Automation Control Conference (IAEAC), 2018: IEEE, pp. 83-87.
[34]R. E. Caetano et al., "Development of Distance Sensors for Diagnosing Air-Gap Anomalies in Synchronous Generators," in 2015 IEEE 24th International Symposium on Industrial Electronics (ISIE), 2015: IEEE, pp. 146-149.
[35]白國伸 ，旋轉機構軸承故障偵測裝置及故障監視系統研製，國立臺灣科技大學電機工程系，碩士論文，台北市，民國一百零一年。