Abstract：Electrical corrosion of Motor bearings has become a serious, industry-wide issue that significantly threatens the reliability and lifetime of inverter-fed electric drive systems. The high-frequency pulse-width-modulated voltages generated by SiC-based inverters induce a common-mode voltage that causes the bearing voltage to exceed the breakdown threshold of the lubricating oil film, resulting in repetitive electric discharge machining (EDM) currents and progressive pitting on the bearing raceways. This paper proposes a novel non-contact active suppression method based on the common-mode transformer (CMT) principle. The motor shaft is treated as a single-turn secondary winding of the CMT, so that a compensating voltage can be injected into the bearing-voltage coupling path via a non-contact magnetic link. As a result, it cancels the bearing voltage and prevents electrical corrosion without the need for physical grounding brushes or conductive grease. First, a high-frequency bearing-voltage model (BVHM) is established to clarify the coupling relationship among the parasitic capacitances of the stator windings, rotor, and frame. The model parameters are extracted from experimental impedance curves measured by a Keysight E4990A impedance analyzer, including the common-mode, differential-mode, winding-to-rotor, and rotor-to-frame impedances. Then, the equivalent circuit, operating principle, and parameter calculation procedure of the proposed active bearing voltage canceller (ABVC) are analyzed. The ABVC consists of a compensation H-bridge circuit and two identical CMTs mounted on both sides of the motor shaft. By synchronizing the ABVC modulation strategy with the inverter's modulation, the injected compensation voltage maintains amplitude and phase alignment with the open-circuit bearing voltage. Second, to further improve the suppression performance, the effects of dead-time distortion and rise-fall time mismatch are investigated. A dead-time compensation strategy and an optimized driving resistor design are proposed to ensure dynamic phase synchronization between the injected voltage and the original bearing voltage during transient switching intervals. The theoretical expressions for the MOSFET gate-driving resistance are derived based on the turn-on and turn-off characteristics, enabling accurate control of the voltage rise and fall slopes. The compensation control scheme ensures that the proposed suppression method remains independent of bearing impedance and is robust to variations in speed, load, temperature, and lubrication state. Third, the CMT design procedure is described, including magnetic-core selection, determination of the turns ratio, and area-product (AP)- based size optimization. The CMTs are designed with nanocrystalline toroidal cores, achieving a working magnetic flux density of 0.38 T and a magnetizing current of 1.04 A under rated conditions. It ensures high magnetic coupling capability while maintaining a compact volume. The proposed design achieves a significantly smaller volume and lower copper loss than conventional passive and active common-mode filters, since the CMT does not carry large phase currents and operates only along the magnetic coupling path. Finally, the proposed suppression method is validated on a 60 kW automotive permanent-magnet synchronous motor (PMSM) test platform. The results show that the proposed method can eliminate the steady- state bearing voltage and reduce transient voltage spikes by approximately 85%. No bearing breakdown or discharge phenomena are observed during long-term operation, verifying the effectiveness and engineering feasibility of the proposed non-contact active suppression approach in preventing bearing electrical erosion.
杨明亮, 程远, 杜博超, 崔淑梅. 基于共模变压器原理的电机轴承电腐蚀非接触式主动抑制方法[J]. 电工技术学报, 2026, 41(12): 4033-4051.
Yang Mingliang, Cheng Yuan, Du Bochao, Cui Shumei. A Non-Contact Active Suppression Method for Motor Bearing Electrical Erosion Based on the Principle of Common-Mode Transformer. Transactions of China Electrotechnical Society, 2026, 41(12): 4033-4051.
[1] Busse D, Erdman J, Kerkman R J, et al.Bearing currents and their relationship to PWM drives[J]. IEEE Transactions on Power Electronics, 1997, 12(2): 243-252. [2] Ong R, Dymond J H, Findlay R D.Comparison of techniques for measurement of shaft currents in rotating machines[J]. IEEE Transactions on Energy Conversion, 1997, 12(4): 363-367. [3] 肖宗鑫, 胡明辉, 周强, 等. 电驱系统轴承电蚀抑制措施研究综述[J]. 电工技术学报, 2025, 40(20): 6552-6576. Xiao Zongxin, Hu Minghui, Zhou Qiang, et al.A review of research on bearing electrical-erosion suppression measures in electric drive systems[J]. Transactions of China Electrotechnical Society, 2025, 40(20): 6552-6576. [4] 迟连强, 张殿海, 赵俊清, 等. 旋转电机轴承电蚀损伤机理与缓解措施研究进展[J]. 电工技术学报, 2024, 39(20): 6409-6430. Chi Lianqiang, Zhang Dianhai, Zhao Junqing, et al.Research progress on the mechanism and mitigation measure of electrical corrosion damage in rotating motor bearings[J]. Transactions of China Electro-technical Society, 2024, 39(20): 6409-6430. [5] 郑丹, 温旭辉, 范涛, 等. 高环境温度高功率密度SiC电机驱动控制器设计与实现[J]. 电工技术学报, 2025, 40(15): 4889-4904. Zheng Dan, Wen Xuhui, Fan Tao, et al.Design and implementation of SiC motor drive controller with high environmental temperature and high power density[J]. Transactions of China Electrotechnical Society, 2025, 40(15): 4889-4904. [6] 夏衍, 孙立鹏, 李军伟, 等. 基于三状态PWM的电动汽车电机驱动系统多模式调制策略研究[J]. 电工技术学报, 2024, 39(4): 1010-1021. Xia Yan, Sun Lipeng, Li Junwei, et al.Research on multi-mode modulation strategy of motor drive system based on tri-state PWM in EV[J]. Transactions of China Electrotechnical Society, 2024, 39(4): 1010-1021. [7] Hava A M, Ün E.A high-performance PWM algo-rithm for common-mode voltage reduction in three-phase voltage source inverters[J]. IEEE Transactions on Power Electronics, 2010, 26(7): 1998-2008. [8] Robles E, Fernandez M, Andreu J, et al.Common-mode voltage mitigation in multiphase electric motor drive systems[J]. Renewable and Sustainable Energy Reviews, 2022, 157: 111971. [9] 孙全增, 张志锋. 双三相永磁同步电机低共模电压模型预测电流控制[J]. 电工技术学报, 2023, 38(14): 3708-3722. Sun Quanzeng, Zhang Zhifeng.Low common-mode voltage model predictive current control for dual three-phase permanent magnet synchronous motor[J]. Transactions of China Electrotechnical Society, 2023, 38(14): 3708-3722. [10] Acosta-Cambranis F, Zaragoza J, Berbel N, et al.Common-mode voltage mitigation strategies using Sigma-Delta modulation in five-phase VSIs[J]. IEEE Transactions on Power Electronics, 2022, 37(10): 11662-11672. [11] Kalaiselvi J, Srinivas S.Bearing currents and shaft voltage reduction in dual-inverter-fed open-end winding induction motor with reduced CMV PWM methods[J]. IEEE Transactions on Industrial Electro-nics, 2015, 62(1): 144-152. [12] Han Yang, Lu Haifeng, Li Yongdong, et al.Analysis and suppression of shaft voltage in SiC-based inverter for electric vehicle applications[J]. IEEE Transactions on Power Electronics, 2019, 34(7): 6276-6285. [13] Jayaraman K, Kumar M.Design of passive common-mode attenuation methods for inverter-fed induction motor drive with reduced common-mode voltage PWM technique[J]. IEEE Transactions on Power Electronics, 2019, 35(3): 2861-2870. [14] Di Piazza M C, Tine G, Vitale G. An improved active common-mode voltage compensation device for induction motor drives[J]. IEEE Transactions on Industrial Electronics, 2008, 55(4): 1823-1834. [15] Kumar M, Jayaraman K.Design of active common mode noise voltage canceler for SiC inverter fed induction motor drive with reduced common mode voltage PWM[C]//2020 IEEE 29th International Symposium on Industrial Electronics (ISIE), Delft, Netherlands, 2020: 695-700. [16] 姜艳姝, 陈希有, 徐殿国, 等. 一种消除PWM逆变器驱动系统中电动机端轴电压和轴承电流的前馈有源滤波器[J]. 中国电机工程学报, 2003, 23(7): 134-138. Jiang Yanshu, Chen Xiyou, Xu Dianguo, et al.A novel feed-forward-type active filter to eliminate shaft voltage and bearing current at motor terminal in a PWM inverter drives[J]. Proceedings of the CSEE, 2003, 23(7): 134-138. [17] Yang Mingliang, Cheng Yuan, Du Bochao, et al.Research on analysis and suppression methods of the bearing current for electric vehicle motor driven by SiC inverter[J]. Energies, 2024, 17(5): 1109. [18] 赵方伟, 王秀和, 赵文良, 等. 内置式永磁同步电机动态偏心故障下的轴电压解析分析和削弱[J]. 电工技术学报, 2022, 37(4): 837-848. Zhao Fangwei, Wang Xiuhe, Zhao Wenliang, et al.Analysis and reduction of shaft voltage in interior permanent magnet synchronous motors under dynamic eccentricity fault[J]. Transactions of China Electrotechnical Society, 2022, 37(4): 837-848. [19] Lee J S, Ahn J M, Lim D K, et al.Novel salient stator pole-shoe structure for reducing shaft-to-frame voltage of the PMSM[J]. IEEE Transactions on Magnetics, 2025, 61(3): 8201404. [20] Lee S T, Park J K, Jeong C L, et al.Shaft-to-frame voltage mitigation method by changing winding-to-rotor parasitic capacitance of IPMSM[J]. IEEE Transactions on Industry Applications, 2019, 55(2): 1430-1436. [21] Vostrov K, Pyrhönen J, Niemelä M, et al.On the application of extended grounded slot electrodes to reduce noncirculating bearing currents[J]. IEEE Transactions on Industrial Electronics, 2022, 70(3): 2286-2295. [22] Êvo M T A, Júnior A M G, Silva C E, et al. Electrostatic shielding for bearing current mitigation-an analysis of its thermal impact on the motor[J]. IEEE Transactions on Industry Applications, 2023, 59(6): 7876-7885. [23] 白保东, 王禹, 陈志雪, 等. 基于电磁屏蔽法变频电机轴承电流抑制研究[J]. 电工技术学报, 2016, 31(7): 33-39. Bai Baodong, Wang Yu, Chen Zhixue, et al.Inhibi-tion of bearing currents in frequency variable motor based on electromagnetic shielding[J]. Transactions of China Electrotechnical Society, 2016, 31(7): 33-39. [24] Stephens M, Chen H, von Jouanne A, et al. Development of novel conductive grease to mitigate PWM inverter-induced bearing currents[C]//2023 IEEE Energy Conversion Congress and Exposition (ECCE), Nashville, TN, USA, 2023: 3186-3193. [25] Janik J R, Saha S, Jackson R L, et al.Rolling element damage and the influence of test conditions and conductive nanoparticle grease additives[C]//2024 IEEE 69th Holm Conference on Electrical Contacts (HOLM), Annapolis, MD, USA, 2024: 1-8. [26] SKF.6012 M/HC5C4 hybrid ceramic deep groove ball bearing[EB/OL].[2025-06-15]. https://www.skf. com/us/products/rolling-bearings/engineered-products/hybrid-bearings/productid-6012%20M%2FHC5C4. [27] Teshale A, Biru G.Overview of shaft voltage and bearing current mitigation methods applied on the victim machine[J]. Electrical Engineering, 2024, 106(2): 1727-1739. [28] He Feng, Xie Guoxin, Luo Jianbin.Electrical bearing failures in electric vehicles[J]. Friction, 2020, 8(1): 4-28. [29] AEGIS. Protect electric motor bearings with shaft grounding rings[EB/OL].[2025-06-15]. https://www. est-aegis.com/. [30] 杨明亮, 程远, 杜博超, 等. 电机轴承电压模拟器和轴承电腐蚀测试系统[J]. 电机与控制学报, 2025, 29(8): 19-30. Yang Mingliang, Cheng Yuan, Du Bochao, et al.Motor bearing voltage simulator and bearing electric corrosion test system[J]. Electric Machines and Control, 2025, 29(8): 19-30. [31] 杨明亮, 程远, 杜博超, 等. 基于端口阻抗特性的电机轴承电压高精度模型[J]. 电工技术学报, 2026, 41(2): 426-441. Yang Mingliang, Cheng Yuan, Du Bochao, et al.High-precision model of motor bearing voltage based on port impedance characteristics[J]. Transactions of China Electrotechnical Society, 2026, 41(2): 426-441. [32] Cui Mingkai, Chen Lei, Pei Yulong, et al.The active gate driver based on hardware closed-loop control for crosstalk suppression of SiC MOSFETs with kelvin-source connection[J]. IEEE Transactions on Power Electronics, 2024, 40(1): 217-226. [33] 高海洋. 基于改进PWM调制策略的三相永磁同步电机系统共模电压抑制研究[D]. 哈尔滨: 哈尔滨工业大学, 2022. Gao Haiyang.Research on common mode voltage suppression of three-phase permanent magnet syn-chronous motor systems based on improved PWM modulation strategy[D]. Harbin: Harbin Institute of Technology, 2022. [34] 卡罗尼尔. 麦克莱曼. 变压器与电感器设计手册, 第四版. 周京华译[M]. 北京: 中国电力出版社, 2014. [35] 梁言. 碳化硅逆变器调速系统轴承电流研究[D]. 徐州: 中国矿业大学, 2019. Liang Yan.Study on bearing current in induction motor drives based on SiC MOSFET[D]. Xuzhou: China University of Mining and Technology, 2019. [36] IEC. Vehicles, boats and internal combustion engines-radio disturbance characteristics-limits and methods of measurement for the protection of on-board receivers: IEC CISPR 25[S]. Geneva: IEC, 2021.
2026, Vol. 41 
