馬達運轉時，其內部可能因為共模雜訊等原因發生放電現象，此時流經軸承的電流便稱為軸承電流，此電流可能造成軸承的損壞。本文針對軸承電流之現象與發生原因進行探討，並分析現有軸承電流之抑制方法，其中在不更動硬體僅修改開關切換方式的抑制方法中，基於現有的空間向量脈波寬度調變(Space Vector Pulse Width Modulation , SVPWM)技術，提出一種新的混合切換式PWM來抑制局部的共模電壓進而降低軸承電流發生率，並以模擬與實驗驗證之。結果顯示混合切換式PWM確實能將局部的共模電壓抑制到傳統SVPWM的三分之一與兩相調變的二分之一，並在低共模區維持軸電壓波形的完整性、減少軸承電流整體發生率。

This research focuses on the suppression of bearing current for permanent magnet (PM) synchronous motors, which is caused by the common mode voltage of a pulse width modulation (PWM) inverter. Firstly, the causes of bearing current and some conventional suppression methods are investigated. Then, a new hybrid-switching PWM method is proposed, which is verified to successfully reduce the common mode voltage to one-third of the conventional space vector PWMs (SVPWMs) and half of two-phase modulation SVPWMs. The overall probability of bearing current is reduced without changing the design of the hardware.

[1] ABB drives, “Technical Guide No.5 Bearing Currents in Modern AC Drive Systems,” 2011.
[2] P.L. ALGER and H.W. SAMSON, “Shaft Current in Electric Machines,” A.I.E.E, 1927.
[3] S. Chen, T. A. Lipo and D. Fitzgerald, “Modeling of Motor Bearing Currents in PWM Inverter Drives,” IEEE Transations on Industry Applications, Vol. 32, No. 6, November/December 1995.
[4] S. Chen, D. Fitzgerald and T. A. Lipo, “Source of Induction Motor Bearing Currents Caused by PWM Inverters,” IEEE Energy Conversion, Vol.11, No.1, March 1995.
[5] D. Busse, J. Erdman, R. J. Kerkman,D. Schlegel, and G. Skibinski, “Bearing Currents and Their Relationship to PWM Drives,” IEEE Transations on Power Electronics, Vol. 12, No. 2, March 1997.
[6] D. Busse, J. Erdman, R. J. Kerkman, D. Schlegel, and G. Skibinski, “System Electrical Parameters and Their Effects on Bearing Currents,” IEEE Transations on Industry Applications, Vol. 33, No. 2, March/April 1997.
[7] 奥山吉彦・藤井秀樹：「インバータ駆動誘導電動機の軸電圧」, 富士時報, Vol.72, No.2 (1999)
[8] R. Schiferl and M. Melfi, “Bearing Current Problems: Causes, Symptoms, and solutions,” Electrical Construction and Maintenance, 2004.
[9] 野口昭治・赤松洋孝：「小型ベアリングの電食に関する研究」, 2006年度精密工学会春季大会学術講演会講演論文集(2006)
[10] AEGIS：「技術コラム（3）最新の電食対策をご紹介」,(2013)
[11] A. Muetze and A. Binder, “Techniques for Measurement of Parameters Relative to Inverter-induced Bearing Currents,” IEEE Transactions on Industry Applications, Vol. 43, No.5, 2007.
[12] 蔡明村等人，「變頻器共模電壓抑制策略與電磁干擾問題之研究」，南台科技大學電機系，西元2003年。
[13] 蔡明村等人，「變頻器高共模雜訊對馬達與周圍敏感設備影響之研究」，南台科技大學電機系，西元2001年。
[14] 謝宏周，「變頻器之共模雜訊分析及其抑制技術研究」，財團法人車輛研究測試中心。
[15] A. Muetze and H.W. Oh, “Application of Static Charge Dissipation to Mitigate Electric Discharge Bearing Currents,” IEEE Transactions on Industry Applications, Vol. 44, No.1, 2008.
[16] SKF絕緣軸承，INSOCOAT系列
[17] SKF混合陶瓷軸承，HC5C3系列
[18] 電気学会技術報告287号：「インバータ駆動誘導電動機の技術的諸問題」 (1988)
[19] 福田交易株式會社：「AEGIS SGR」 (2014)
[20] D. F. Busse, M. E. Erdman, R. J. Kerkman, D. W. Schlegel, and G. L. Skibinski, “An Evaluation of the Electrostatic Shielded Induction Motor: a Solution for Rotor Shaft Voltage Buildup and Bearing Current,” IEEE Transactions on Industry Applications, Vol. 33, No. 6 ,1997
[21] 延昇，「變頻器相關的問與答(39)」，電機月刊，第九卷，第十一期，1999年11月。
[22] 前谷達男：「PWMインバータか駆動ブラシレスDCモータのベアリング電食に関する研究」,大阪府立大学 (2013)
[23] 磯村宜典：「空調用ファンモータのベアリンク電食に関する研究」,鹿児島大学 (2014)
[24] D. C. Ludois and J. K. Reed, “Brushless Mitigation of Bearing Currents in Electric Machines Via Capacitively Coupled Shunting,” IEEE Transactions on Industry Applications, 2014.
[25] B. Bai, Y. Wang, and X.Wang, “Suppression for Discharging Bearing Current in Variable-Frequency Motors Based on Electromagnetic Shielding Slot Wedge,” IEEE Transacions on Magnetics, 2014.
[26] A.L. Julian, G. Oriti and T.A. Lipo,“Elimination of Common-mode Voltage in Three-phase Sinusoidal Power Converters,” IEEE Transactions on Power Electronics , September. 1999.
[27] S. Ogasawara, H. Ayano, H. Akagi,“An Active Circuit for Cancellation of Common-mode Voltage Generated by a PWM Inverter,” IEEE Transactions on Power Electronics, September. 1998.
[28] 吳峻仲，「變頻器驅動對交流馬達軸電流改善之研究」，逢甲大學，西元2008年。
[29] C. R. Paul,“Introduction to Electromagnetic Compatibility,” John Wiley＆Sons, 1992.
[30] 許溢适，劉昌煥，「AC伺服系統的理論與設計實務」，第四版，文笙書局，西元1999年。
[31] 陳泰羽，「兩相調變之向量控制永磁同步馬達驅動器的研製」，臺北科技大學，西元2011年。
[32] 陳景熙，元鵬，周璟，張凱，「一種低共模電磁干擾SVPWM法的研究」，高電壓技術，西元2008年。
[33] A. M. Hava,“A High-Performance PWM Algorithm for Common-Mode Voltage Reduction in Three-Phase Voltage Source Inverters,” IEEE Transactions on Power Electronics, Vol. 26, No. 7, July 2011.
[34] A. M. Hava,“Performance Analysis of Reduced Common-Mode Voltage PWM Methods and Comparison With Standard PWM Methods for Three-Phase Voltage-Source Inverters,” IEEE Transactions on Power Electronics, Vol. 24, No. 1, January 2009.
[35] Y. S. Lai and F. S. Shyu, “Optimal common-mode voltage reduction PWM technique for inverter control with consideration of the dead-time effects Part I: Basic development,” IEEE Transations on Industry Applications, Vol. 40, No. 6, November/December 2003.
[36] K. S. Narayana, A. K. Rao, and K. Satyanarayana, “Novel AZSPWM algorithms based VCIMD for reduced CMV variations,” International Journal of Power Electronics and Drive Systems, Vol. 3, No. 1, March. 2013
[37] A. M. Hava, and N. O. Çetin, “A Generalized Scalar PWM Approach With Easy Implementation Features for Three-Phase, Three-Wire Voltage-Source Inverters,” IEEE Transactions on Power Electronics, Vol. 26, No. 5, May 2011.
[38] K.Y. Chen and M.S. Hsieh, “Generalized Minimum Common-Mode Voltage PWM for Two-Level Multiphase VSIs Considering Reference Order, ” IEEE Transavtions on Power Electronics, Vol. 32, No. 8, August 2017.
[39] Microchip, “dsPIC30F Family Reference Manual,” 2003.
[40] Microchip, “dsPIC30F4011/4012 Data Sheet,” 2010.