A Diagnosis Method for Power Switch and Current Sensor Faults in Grid-Connected Three-Level Neutral-Point Clamped Inverters Based on Adaptive Sliding Mode Observer
Xu Shuiqing1, Xu Xiaofan1, He Yigang2, Chai Yi3
1. College of Electrical Engineering and Automation Hefei University of Technology Hefei 230009 China; 2. School of Electrical Engineering and Automation Wuhan University Wuhan 430072 China; 3. State Key Laboratory of Power Transmission Equipment Technology Chongqing University Chongqing 400044 China
Abstract:The grid-connected three-level neutral-point clamped (3L-NPC) inverter is widely used in grid-connected systems for new energy generation due to its advantages such as low output voltage and current harmonics. However, an open-circuit fault in power switch or a fault in the current sensor within the inverter can lead to a decrease in system performance and may even trigger significant safety incidents within the power grid. Nowadays, most of the fault diagnosis methods for 3L-NPC inverters focus on single-fault diagnosis. Therefore, this paper presents a simultaneous fault diagnosis method for both the power switch open-circuit fault and current sensor fault in 3L-NPC inverter based on an adaptive sliding mode observer. Firstly, an adaptive sliding mode observer with fast convergence speed and significant chattering suppression is designed to accurately estimate the three-phase current value in normal state. Then, fault diagnosis variables are designed using estimated and actual currents.In the absence of a fault in the inverter, the fault detection variable dx stays within the adaptive threshold range. However, in the event of a fault, the detection variable dx rapidly surpasses the adaptive threshold. The faulty phase can be determined based on the absolutemaximum values of the fault detection variables ra, rb and rc. Additionally, if the sum of the three-phase currents falls within the adaptive threshold range, it signifies a power switch open-circuit fault on the faulty phase. Conversely, it indicates a sensor fault has occurred on the faulty phase. On the basis of completing the fault detection, we further carry out fault identification. In the event of a power switch open-circuit fault in the inverter, the specific location of the faulty power switch can be determined using the fault localization variable wx. In cases of a current sensor fault within the inverter, a rapid identification of the type of current sensor fault can be achieved by combining the fault localization variable wx with the fault identification variable Bx. Through the establishment of a hardware-in-the-loop experimental platform, we have successfully validated the effectiveness of the fault diagnostic algorithm presented in this paper. The diagnostic algorithm demonstrates a remarkable trait of not producing false alarms even under conditions involving DC-side voltage fluctuations, grid voltage fluctuations, and inductive parameter imbalances, showcasing its robustness. In conclusion, after conducting experimental verification and analysis, it can be affirmed that the fault diagnosis method devised in this paper possesses the following advantages: (1) The simultaneous diagnosis method of power switch open-circuit faults and current sensor faults of 3L-NPC inverter is proposed, which not only prevents false fault reports arising from the mutual influence of these two fault types in a single diagnosis but also facilitates prompt implementation of follow-up maintenance measures after detecting the faults. (2) Through the design of an innovative adaptive convergence law, we have constructed an adaptive sliding mode observer with rapid convergence and substantial jitter suppression. This enhancement results in more precise current observations, thereby ensuring the effectiveness of the fault diagnosis method. (3) A novel fault detection and identification method is introduced. Through the utilization of only actual and estimated current values, without the need for intricate data processing or additional hardware configurations, fault detection and diagnostic variables have been designed, enabling rapid and accurate fault diagnosis.
许水清, 许晓凡, 何怡刚, 柴毅. 基于自适应滑模观测器的中点钳位型三电平并网逆变器开关管和电流传感器故障诊断[J]. 电工技术学报, 2024, 39(13): 4066-4078.
Xu Shuiqing, Xu Xiaofan, He Yigang, Chai Yi. A Diagnosis Method for Power Switch and Current Sensor Faults in Grid-Connected Three-Level Neutral-Point Clamped Inverters Based on Adaptive Sliding Mode Observer. Transactions of China Electrotechnical Society, 2024, 39(13): 4066-4078.
[1] 卫炜, 高瞻, 赵牧天, 等. 基于切换调制波的三电平有源中点钳位逆变器优化容错技术研究[J]. 电工技术学报, 2022, 37(15): 3818-3833. Wei Wei, Gao Zhan, Zhao Mutian, et al.Research on optimal fault-tolerant technique for three-level active-neutral-point-clamped inverter based on switching modulation wave[J]. Transactions of China Electrote-chnical Society, 2022, 37(15): 3818-3833. [2] 王金平, 刘斌, 董浩, 等. 中点钳位型三电平逆变器基于调制波分解的调制策略[J]. 电工技术学报, 2023, 38(12): 3221-3233. Wang Jinping, Liu Bin, Dong Hao, et al.A modulation strategy based on modulation wave decomposition for neutral point clamped three-level inverter[J]. Transactions of China Electrotechnical Society, 2023, 38(12): 3221-3233. [3] 马铭遥, 凌峰, 孙雅蓉, 等. 三相电压型逆变器智能化故障诊断方法综述[J]. 中国电机工程学报, 2020, 40(23): 7683-7698. Ma Mingyao, Ling Feng, Sun Yarong, et al.Review of intelligent fault diagnosis methods for three-phase voltage-mode inverters[J]. Proceedings of the CSEE, 2020, 40(23): 7683-7698. [4] Pecina Sánchez J A, Campos-Delgado D U, Espinoza-Trejo D R, et al. Fault diagnosis in grid-connected PV NPC inverters by a model-based and data processing combined approach[J]. IET Power Electronics, 2019, 12(12): 3254-3264. [5] Wu Xun, Chen Chunyang, Chen Tefang, et al.A fast and robust diagnostic method for multiple open-circuit faults of voltage-source inverters through line voltage magnitudes analysis[J]. IEEE Transactions on Power Electronics, 2020, 35(5): 5205-5220. [6] 夏一文, 张卓然, 张健, 等. 基于反电势电流的电励磁双凸极电机驱动电路单管开路故障诊断研究[J]. 电工技术学报, 2020, 35(23): 4888-4897. Xia Yiwen, Zhang Zhuoran, Zhang Jian, et al.Research on single power switch open circuit fault diagnosis of doubly salient eletromagnetic motor drive circuit based on the back electromotive force current[J]. Transactions of China Electrotechnical Society, 2020, 35(23): 4888-4897. [7] Lu Bin, Sharma S K.A literature review of IGBT fault diagnostic and protection methods for power inverters[J]. IEEE Transactions on Industry Applica-tions, 2009, 45(5): 1770-1777. [8] Zhou Yang, Zhao Jin, Song Yujin, et al.A seasonal-trend-decomposition-based voltage-source-inverter open-circuit fault diagnosis method[J]. IEEE Transa-ctions on Power Electronics, 2022, 37(12): 15517-15527. [9] 刘座辰, 林磊, 殷天翔, 等. 一种模块化多电平换流器子模块开路故障的快速检测与诊断方法[J]. 电工技术学报, 2022, 37(19): 4883-4894. Liu Zuochen, Lin Lei, Yin Tianxiang, et al.A fast open-circuit fault detection and diagnosis method for sub-modules of modular multilevel converters[J]. Transactions of China Electrotechnical Society, 2022, 37(19): 4883-4894. [10] 徐小健, 于飞. 基于输出电压轨迹的三相逆变器开关管开路故障诊断[J]. 中国电机工程学报, 2024, 44(3): 1106-1117. Xu Xiaojian, Yu Fei.A fault diagnosis method based on output voltage patterns for switch open-circuit fault of three-phase inverters[J]. Proceedings of the CSEE. 2024, 44(3): 1106-1117. [11] 李兵, 崔介兵, 何怡刚, 等. 基于能量谱熵及小波神经网络的有源中性点钳位三电平逆变器故障诊断[J]. 电工技术学报, 2020, 35(10): 2216-2225. Li Bing, Cui Jiebing, He Yigang, et al.Fault diagnosis of active neutral point clamped three-level inverter based on energy spectrum entropy and wavelet neural network[J]. Transactions of China Electrotechnical Society, 2020, 35(10): 2216-2225. [12] Kou Lei, Liu Chuang, Cai Guowei, et al.Fault diagnosis for open-circuit faults in NPC inverter based on knowledge-driven and data-driven approaches[J]. IET Power Electronics, 2020, 13(6): 1236-1245. [13] Hu Yusong, Cheng Shu, Wu Xun, et al.A diagnostic method for open-circuit faults of loads and semiconductors in 3L-NPC inverters[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2023, 11(3): 2577-2590. [14] Zhou Xinxiu, Sun Jun, Cui Peiling, et al.A fast and robust open-switch fault diagnosis method for variable-speed PMSM system[J]. IEEE Transactions on Power Electronics, 2021, 36(3): 2598-2610. [15] Caseiro L M A, Mendes A M S, Cruz S M A. Cooperative and dynamically weighted model predictive control of a 3-level uninterruptible power supply with improved performance and dynamic response[J]. IEEE Transactions on Industrial Electronics, 2020, 67(6): 4934-4945. [16] Zhang Zeliang, Hu Yihua, Luo Guangzhao, et al.An embedded fault-tolerant control method for single open-switch faults in standard PMSM drives[J]. IEEE Transactions on Power Electronics, 2022, 37(7): 8476-8487. [17] 李宁, 李颖晖, 朱喜华, 等. 混杂系统理论及其在三相逆变电路开路故障诊断中的应用[J]. 电工技术学报, 2014, 29(6): 114-119. Li Ning, Li Yinghui, Zhu Xihua, et al.Fault diagnosis for power electronic circuits based on mixed logic dynamic model and incident identification vector[J]. Transactions of China Electrotechnical Society, 2014, 29(6): 114-119. [18] 陈勇, 张建建, 陈章勇. 基于电流观测器的三相逆变电路开路故障在线诊断[J]. 电工技术学报, 2019, 34(增刊2): 609-617. Chen Yong, Zhang Jianjian, Chen Zhangyong.A current observer based on-line open-fault diagnosis for three-phase inverter[J]. Transactions of China Electrotechnical Society, 2019, 34(S2): 609-617. [19] 陈超波, 王霞霞, 高嵩, 等. 基于区间滑模观测器的逆变器开路故障诊断方法[J]. 中国电机工程学报, 2020, 40(14): 4569-4579. Chen Chaobo, Wang Xiaxia, Gao Song, et al.A diagnosis method for open-circuit faults in inverters based on interval sliding mode observer[J]. Proceedings of the CSEE, 2020, 40(14): 4569-4579. [20] 许水清, 黄文展, 何怡刚, 等. 基于自适应滑模观测器的中点钳位型三电平并网逆变器开路故障诊断[J]. 电工技术学报, 2023, 38(4): 1010-1022. Xu Shuiqing, Huang Wenzhan, He Yigang, et al.Open-circuit fault diagnosis method of neutral point clamped three-level grid-connected inverter based on adaptive sliding mode observer[J]. Transactions of China Electrotechnical Society, 2023, 38(4): 1010-1022. [21] Yang Shaoyong, Xiang Dawei, Bryant A, et al.Condition monitoring for device reliability in power electronic converters: a review[J]. IEEE Transactions on Power Electronics, 2010, 25(11): 2734-2752. [22] 孙德博, 胡艳芳, 牛峰, 等. 开关磁阻电机调速系统故障诊断和容错控制方法研究现状及展望[J]. 电工技术学报, 2022, 37(9): 2211-2229. Sun Debo, Hu Yanfang, Niu Feng, et al.Status and prospect of fault diagnosis and tolerant control methods for switched reluctance motor drive system[J]. Transactions of China Electrotechnical Society, 2022, 37(9): 2211-2229. [23] 许水清, 刘锋, 何怡刚, 等. 基于自适应滑模观测器的新能源汽车驱动系统电流传感器微小故障诊断[J].中国电机工程学报, 2023, 43(18): 7277-7288. Xu Shuiqing, Liu Feng, He Yigang, et al.Minor fault diagnosis for current sensor of new energy vehicle drive system based on adaptive sliding mode observer[J]. Proceedings of the CSEE, 2023, 43(18): 7277-7288. [24] Wang Wei, Tian Weijie, Wang Zheng, et al.A fault diagnosis method for current sensors of primary permanent-magnet linear motor drives[J]. IEEE Transactions on Power Electronics, 2021, 36(2): 2334-2345. [25] Li Jianhua, Du Bochao, Zhao Tianxu, et al.Current sensor fault-tolerant control for five-phase PMSM drives based on third-harmonic space[J]. IEEE Transactions on Industrial Electronics, 2022, 69(10): 9827-9837. [26] Jlassi I, Estima J O, El Khil S K, et al. A robust observer-based method for IGBTs and current sensors fault diagnosis in voltage-source inverters of PMSM drives[J]. IEEE Transactions on Industry Applications, 2017, 53(3): 2894-2905. [27] Jlassi I, Cardoso A J M. A single method for multiple IGBT, current, and speed sensor faults diagnosis in regenerative PMSM drives[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2020, 8(3): 2583-2599. [28] Khojet El Khil S, Jlassi I, Marques Cardoso A J, et al. Diagnosis of open-switch and current sensor faults in PMSM drives through stator current analysis[J]. IEEE Transactions on Industry Applications, 2019, 55(6): 5925-5937. [29] Gou Bin, Xu Yan, Xia Yang, et al.An online data-driven method for simultaneous diagnosis of IGBT and current sensor fault of three-phase PWM inverter in induction motor drives[J]. IEEE Transactions on Power Electronics, 2020, 35(12): 13281-13294. [30] Li Zhan, Wheeler P, Watson A, et al.A fast diagnosis method for both IGBT faults and current sensor faults in grid-tied three-phase inverters with two current sensors[J]. IEEE Transactions on Power Electronics, 2020, 35(5): 5267-5278. [31] Gou Bin, Xu Yan, Xia Yang, et al.An intelligent time-adaptive data-driven method for sensor fault diagnosis in induction motor drive system[J]. IEEE Transactions on Industrial Electronics, 2019, 66(12): 9817-9827. [32] Xiao Tengfei, Li Xiaodong, Wang Shuqiang.Dominant-modes-based sliding-mode observer for estimation of temperature distribution in rapid thermal processing system[J]. IEEE Transactions on Industrial Informatics, 2019, 15(5): 2673-2681. [33] Gong Chao, Hu Yihua, Gao Jinqiu, et al.An improved delay-suppressed sliding-mode observer for sensorless vector-controlled PMSM[J]. IEEE Transactions on Industrial Electronics, 2020, 67(7): 5913-5923. [34] Liang Donglai, Li Jian, Qu Ronghai, et al.Adaptive second-order sliding-mode observer for PMSM sensorless control considering VSI nonlinearity[J]. IEEE Transactions on Power Electronics, 2018, 33(10): 8994-9004. [35] Choi U M, Lee J S, Blaabjerg F, et al.Open-circuit fault diagnosis and fault-tolerant control for a grid-connected NPC inverter[J]. IEEE Transactions on Power Electronics, 2016, 31(10): 7234-7247. [36] Choi U M, Jeong H G, Lee K B, et al.Method for detecting an open-switch fault in a grid-connected NPC inverter system[J]. IEEE Transactions on Power Electronics, 2012, 27(6): 2726-2739.