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  

Open-Circuit Fault Diagnosis Method of Neutral Point Clamped Three-Level Grid-Connected Inverter Based on Adaptive Sliding Mode Observer

作　　者：许水清 黄文展 何怡刚[1] 胡友强 程庭莉 Xu Shuiqing;Huang Wenzhan;He Yigang;Hu Youqiang;Cheng Tingli(College of Electrical Engineering and Automation Hefei University of Technology,Hefei 230009 China;State Key Laboratory of Power Transmission Equipment and System Security and New Technology,Chongqing 400044 China)

机构地区：[1]合肥工业大学电气与自动化工程学院,合肥230009 [2]输配电装备及系统安全与新技术国家重点实验室(重庆大学),重庆400044

出　　处：《电工技术学报》2023年第4期1010-1022,共13页Transactions of China Electrotechnical Society

基　　金：国家重点研发计划项目(2016YFF0102200);国家自然科学基金重点项目(51637004);国家自然科学基金联合基金重点项目(U2034209);国家自然科学基金面上项目(62273128);国家自然科学基金青年项目(61803140);中国博士后科学基金面上项目(2020M682474)资助。

摘　　要：为提高中点钳位型(NPC)三电平并网逆变器故障诊断的准确性和鲁棒性,该文针对其开关管单管和双管故障,提出一种基于自适应滑模观测器的开路故障诊断方法。该方法首先建立逆变器在正常状态和开关管故障状态下的混合逻辑动态模型;其次设计收敛速度快且显著抑制抖振的自适应滑模观测器精确估计正常状态下的三相电流值;然后利用实际系统和观测器的输出电流提出基于电流形态因子的故障检测方法;最后根据电流残差来构造故障定位变量进行故障定位。在此基础上,通过建立前次故障状态的自适应滑模观测器实现双开关管开路故障诊断。该文提出的方法能够同时实现单管和双管开路故障诊断,诊断速度快、鲁棒性强,且避免增加额外传感器。实验结果验证了该文所提诊断方法的鲁棒性和有效性。Neutral-point-clamped(NPC) three-level grid-connected inverter plays a pivotal role as an effective interface connecting new energy generation system and grid. However, the failure of any switch will cause the inverter to fail to work normally, resulting in significant economic losses and safety accidents. Some open-circuit fault diagnosis methods of NPC three-level inverters are proposed in recent years. However, these methods are heavily dependent on the quantity of the data, have a long diagnosis time, or only realize single switch fault diagnosis. This paper proposed a diagnosis method based on an adaptive sliding mode observer for single-switch and double-switches faults.In this method, the mixed logic dynamic models of the inverter in the normal state and the open-circuit fault state were established at first, respectively. Then, an adaptive sliding mode observer with fast convergence and significant chattering suppression was designed to estimate the three-phase current in normal states. Subsequently,a fault detection method based on the current form factor was proposed using the output current of the actual system and the observer. Finally, the fault localization variable was constructed according to the current residual for fault localization. On this basis, the open-circuit fault diagnosis of double switches was realized by establishing an adaptive sliding mode observer of the previous fault state.A hardware-in-loop experiment platform is built to verify the effectiveness and robustness of the proposed method. When the inverter works normally, the fault detection variable Mais smaller than the adaptive threshold Ta, and the detection variable ηa=ηb=ηc. When Qa1open-circuit fault occurs, the output currents are distorted to a certain extent, and the detection variable Maexceeds the adaptive threshold Ta. Meanwhile, the detection variable ηa>ηb,ηcindicates that fault occurs in phase-a of the inverter. At the same time, the fault location variable Pa=3/2 can locate the open-circuit fault according to

关 键 词：NPC三电平并网逆变器 开路故障 自适应滑模观测器 电流形态因子 

分 类 号：TM464[电气工程—电器]