基于故障状态变量积分的级联H桥变流器功率单元开路故障检测  

Fault State Variables Integral Based Open-circuit Fault Detection for Power Unit of Cascaded H-bridge Converter

作　　者：肖遥遥 沈煜 杨帆 左文平[1] 文劲宇[1] 杨志淳 XIAO Yaoyao;SHEN Yu;YANG Fan;ZUO Wenping;WEN Jinyu;YANG Zhichun(State Key Laboratory of Advanced Electromagnetic Engineering and Technology(Huazhong University of Science and Technology),Wuhan 430074,Hubei Province,China;State Grid Hubei Electric Power Co.,Ltd.,Research Institute,Wuhan 430077,Hubei Province,China)

机构地区：[1]强电磁工程与新技术国家重点实验室(华中科技大学),湖北省武汉市430074 [2]国网湖北省电力有限公司电力科学研究院,湖北省武汉市430077

出　　处：《电网技术》2021年第11期4213-4223,共11页Power System Technology

基　　金：湖北省技术创新重大专项项目(2019AAA015)。

摘　　要：级联H桥型变流器(cascaded H-bridge converter,CHBC)被广泛应用于中压大容量领域。对CHBC功率单元绝缘栅双极型晶体管(insulated gate bipolar transistor,IGBT)开路故障的实时快速检测是提高CHBC的运行稳定性和供电可靠性的关键技术,提出了一种基于故障状态变量积分的开路故障检测方法。首先根据功率单元IGBT开路故障外特性建立CHBC开路故障下的数学模型;然后分析了检测方法的原理以及干扰因素;定义故障状态变量并对其积分以消除干扰因素的影响;设定不同积分量的阈值实现功率单元IGBT开路故障的检测;最后在PSCAD/EMTDC中验证了该检测方法的有效性。仿真结果表明:该检测方法可以在半个电流基波周期附近完成一个或多个IGBT开路故障的检测,并且不会因为CHBC运行工况的切换而发生误判,具有较好的鲁棒性。此外,该方法无需添加额外的传感器,具有经济性。The cascaded H-bridge converter(CHBC) has been used in the field of medium voltage with large capacity.The real-time fast detection for IGBT open-circuit faults in the power units of CHBC is the key technology to improve the stability and power distribution reliability of CHBC. This paper proposes a fault state variables integral based detection for open-circuit faults. Firstly, according to the external characteristics of power units in the fault states, a mathematical model of CHBC in the fault condition was established. Then,the primary detection principles of the open circuit faults and the various interference factors were analyzed. The fault state variables were defined and integrated to eliminate the influence of various interference factors. The thresholds of different integration quantities were chosen to detect the IGBT open-circuit faults in the power unit. Finally, test results in the PSCAD/EMTDC illustrated the validity of the proposed method. The simulation results show that the proposed detection method is able to complete the one or more detections of IGBT open-circuit faults in nearly half of the current fundamental wave cycle, and that it will not misjudge when the CHBC operating condition changes, a good robustness. In addition, this method does not need to add additional sensors, which is economical.

关 键 词：级联H桥变流器 开路故障快速检测 故障状态变量 积分阈值 鲁棒性 

分 类 号：TM721[电气工程—电力系统及自动化]