Abstract：The unbalanced phase currents of a multiphase permanent magnet synchronous motor (PMSM) generate large torque fluctuations when an open-circuit or short-circuit fault occurs, which causes the whole system to oscillate or even not continue operating. A novel field-oriented control strategy based on disturbance- observer (DOB-FOC) is proposed to restrain torque fluctuations in the five-phase PMSM with third harmonic back electromotive forces (EMF) under open-circuit and short-circuit fault conditions. Firstly, a fundamental PMSM model with open-circuit fault is built in the synchronous rotating frame using an orthogonal reduced-order transformation matrix. The third harmonic back EMF and short-circuit current are recognized as disturbances. Secondly, a disturbance observer is designed. Then, a feedforward compensatory current obtained from the estimated disturbances is added to the q-axis current reference. Finally, the torque fluctuations caused by the fault can be restrained effectively, and the PMSM with the proposed strategy can operate well under open-circuit and short-circuit faults. Simulation shows that when the third harmonic back EMF is 0 or 20% of the fundamental amplitude, DOB-FOC can effectively suppress the fluctuating torque caused by open-circuit and short-circuit faults. Therefore, whether the back EMF contains the third harmonics, the faulty motor with DOB-FOC has a similar steady-state performance in healthy conditions. Experimental results demonstrate the feasibility and effectiveness of the proposed strategy. When the open-circuit or short-circuit fault occurs, the proposed DOB-FOC strategy is activated at once, and the fluctuating torque is restrained to 0.14 N·m and 0.19 N·m, respectively. When the load steps between 3 N·m and 5 N·m, the d-axis current almost remains unchanged, the q-axis current is like that under healthy conditions, and the response time is 170 ms. During the reference speed step changes, the DOB-FOC strategy significantly reduces the fault impact on the speed performance. Its dynamic performance is similar to that under healthy conditions, and its response time is 240 ms. The following conclusions can be drawn from the theoretical analysis, simulation, and experimental results. (1) The proposed strategy can effectively suppress the fluctuating torque caused by the third harmonic back EMF under open-circuit or short-circuit faults. (2) DOB can effectively estimate torque fluctuations caused by short-circuit current and observe the disturbance caused by two-phase faults without additional hardware support. (3) The proposed strategy is suitable for PMSM with only fundamental back EMF or third harmonic back EMF.
[1] 卢浩, 杜怿, 刘新波, 等. 磁场调制型双馈无刷混合励磁电机及其静态性能分析[J]. 电工技术学报, 2020, 35(14): 2969-2978. Lu Hao, Du Yi, Liu Xinbo, et al.Static performance analysis of magnetic field-modulated doubly-fed brushless hybrid excitation motor[J]. Transactions of China Electrotechnical Society, 2020, 35(14): 2969-2978. [2] 周华伟, 叶晨, 陈铖, 等. 基于转子磁链观测器的五相容错PMSM开路故障下的无位置传感器控制[J]. 电工技术学报, 2023, 38(2): 422-434. Zhou Huawei, Ye Chen, Chen Cheng, et al.Rotor-flux observer based sensorless control of five-phase fault-tolerant PMSM with open-circuit fault[J]. Transactions of China Electrotechnical Society, 2023, 38(2): 422-434. [3] 周长攀, 刘海峰, 景国秀, 等. 双三相永磁同步电机缺相容错运行虚拟矢量间接修正方法及其在直接转矩控制中应用[J]. 电工技术学报, 2023, 38(2): 451-464. Zhou Changpan, Liu Haifeng, Jing Guoxiu, et al.The indirect correction method of virtual vectors for dual three-phase permanent magnet synchronous motors under the open-phase fault and its application in the direct torque control[J]. Transactions of China Electrotechnical Society, 2023, 38(2): 451-464. [4] 孙玉华, 赵文祥, 吉敬华, 等. 高转矩性能多相组永磁电机及其关键技术综述[J]. 电工技术学报, 2023, 38(6): 1403-1420. Sun Yuhua, Zhao Wenxiang, Ji Jinghua, et al.Overview of multi-star multi-phase permanent magnet machines with high torque performance and its key technologies[J]. Transactions of China Electrotech- nical Society, 2023, 38(6): 1403-1420. [5] Wu Fan, Tong Chengde, Sui Yi, et al.Influence of third harmonic back EMF on modeling and remediation of winding short circuit in a multiphase PM machine with FSCWs[J]. IEEE Transactions on Industrial Electronics, 2016, 63(10): 6031-6041. [6] Zhao Meiling, Liu Guohai, Chen Qian, et al.Fault- tolerant control of a triple redundant PMA-SynRM driven under single-phase open-circuit by mono- inverter[J]. IEEE Transactions on Power Electronics, 2021, 36(10): 11593-11605. [7] 匡志, 杜博超, 徐浩, 等. 十五相永磁同步电机的驱动控制与容错运行[J]. 电工技术学报, 2019, 34(13): 2734-2743. Kuang Zhi, Du Bochao, Xu Hao, et al.Drive control and fault-tolerant operation of fifteen phase per- manent magnet synchronous motors[J]. Transactions of China Electrotechnical Society, 2019, 34(13): 2734-2743. [8] 刘自程, 李永东, 郑泽东. 多相电机控制驱动技术研究综述[J]. 电工技术学报, 2017, 32(24): 17-29. Liu Zicheng, Li Yongdong, Zheng Zedong.Control and drive techniques for multiphase machines: a review[J]. Transactions of China Electrotechnical Society, 2017, 32(24): 17-29. [9] Park H, Kim T, Suh Y.Fault-tolerant control methods for reduced torque ripple of multiphase BLDC motor drive system under open-circuit faults[J]. IEEE Transactions on Industry Applications, 2022, 58(6): 7275-7285. [10] 彭金融, 毛行奎, 崔文玲, 等. 基于插入无源二端口网络的噪声源阻抗提取方法研究[J]. 电工技术学报, 2023, 38(2): 523-532. Peng Jinrong, Mao Xingkui, Cui Wenling, et al.Research on noise soure impedance extraction method based on inserting passive two-port network[J]. Transactions of China Electrotechnical Society, 2023, 38(2): 523-532. [11] Wang Huanran, Gu Chunyang, Wang Shuo, et al.Single-phase short-circuit fault tolerant control for five-phase permanent magnet machines with copper loss reduction[J]. IEEE Transactions on Industrial Electronics, 2023, 70(11): 11087-11097. [12] Bermudez M, Gonzalez-Prieto I, Barrero F, et al.Open-phase fault-tolerant direct torque control technique for five-phase induction motor drives[J]. IEEE Transactions on Industrial Electronics, 2017, 64(2): 902-911. [13] Bermudez M, Gonzalez-Prieto I, Barrero F, et al.An experimental assessment of open-phase fault-tolerant virtual-vector-based direct torque control in five- phase induction motor drives[J]. IEEE Transactions on Power Electronics, 2018, 33(3): 2774-2784. [14] Zhang Li, Fan Ying, Cui Ronghua, et al.Fault- tolerant direct torque control of five-phase FTFSCW- IPM motor based on analogous three-phase SVPWM for electric vehicle applications[J]. IEEE Transactions on Vehicular Technology, 2018, 67(2): 910-919. [15] 刘国海, 曹彦琳, 周华伟, 等. 基于新型开关表的五相永磁同步电机容错直接转矩控制[J]. 中国电机工程学报, 2021, 41(18): 6399-6408. Liu Guohai, Cao Yanlin, Zhou Huawei, et al.Novel switching-table based fault tolerant DTC for five- phase PMSM[J]. Proceedings of the CSEE, 2021, 41(18): 6399-6408. [16] Zhang Li, Zhu Xiaoyong, Cui Ronghua, et al.A generalized open-circuit fault-tolerant control strategy for FOC and DTC of five-phase fault-tolerant permanent-magnet motor[J]. IEEE Transactions on Industrial Electronics, 2022, 69(8): 7825-7836. [17] Tian Bing, Wei Jiadan, Molinas M, et al.Neutral voltage modeling and its remediation for five-phase PMSMs under single-phase short-circuit fault tolerant control[J]. IEEE Transactions on Transportation Electrification, 2022, 8(4): 4534-4548. [18] Tian Bing, An Quntao, Duan Jiandong, et al.Decoupled modeling and nonlinear speed control for five-phase PM motor under single-phase open fault[J]. IEEE Transactions on Power Electronics, 2017, 32(7): 5473-5486. [19] Zhou Huawei, Zhao Wenxiang, Liu Guohai, et al.Remedial field-oriented control of five-phase fault- tolerant permanent-magnet motor by using reduced- order transformation matrices[J]. IEEE Transactions on Industrial Electronics, 2017, 64(1): 169-178. [20] 高宏伟, 杨贵杰, 刘剑. 三次谐波注入式五相永磁同步电机矢量控制策略[J]. 中国电机工程学报, 2014, 34(24): 4101-4108. Gao Hongwei, Yang Guijie, Liu Jian.A vector control strategy for five-phase PMSM with third harmonic injection[J]. Proceedings of the CSEE, 2014, 34(24): 4101-4108. [21] 陈前, 夏雨航, 赵文祥, 等. 采用无差拍电流跟踪的五相梯形反电动势永磁电机开路容错控制[J]. 电工技术学报, 2022, 37(2): 368-379. Chen Qian, Xia Yuhang, Zhao Wenxiang, et al.Open-circuit fault-tolerant control for five-phase permanent magnet motors with trapezoidal back-EMF by deadbeat current tracking[J]. Transactions of China Electrotechnical Society, 2022, 37(2): 368-379. [22] 熊聪, 许海平, 周鹏, 等. 五相永磁同步电机单相开路故障的容错矢量控制策略[J]. 中国电机工程学报, 2019, 39(23): 7055-7064, 7118. Xiong Cong, Xu Haiping, Zhou Peng, et al.Fault-tolerant field oriented control for five-phase permanent-magnet motors under single phase open fault[J]. Proceedings of the CSEE, 2019, 39(23): 7055-7064, 7118. [23] Xiong Cong, Guan Tao, Zhou Peng, et al.A fault-tolerant FOC strategy for five-phase SPMSM with minimum torque ripples in the full torque operation range under double-phase open-circuit fault[J]. IEEE Transactions on Industrial Electronics, 2020, 67(11): 9059-9072. [24] Liu Guohai, Lin Zhipeng, Zhao Wenxiang, et al.Third harmonic current injection in fault-tolerant five-phase permanent-magnet motor drive[J]. IEEE Transactions on Power Electronics, 2018, 33(8): 6970-6979. [25] Ginoya D, Shendge P D, Phadke S B.Sliding mode control for mismatched uncertain systems using an extended disturbance observer[J]. IEEE Transactions on Industrial Electronics, 2014, 61(4): 1983-1992. [26] Huang Linsen, Ji Jinghua, Zhao Wenxiang, et al.Duty-ratio-based direct torque control with enhanced harmonic current suppression for dual-three-phase permanent magnet motor[J]. IEEE Transactions on Power Electronics, 2022, 37(9): 11098-11108.
2024, Vol. 39 
