应用于STATCOM的级联U-Cell拓扑直流电压控制策略  

Voltage control strategy of cascaded U-Cell topology STATCOM

作　　者：王颖杰 薛道路 焦岚轶 廖国强 齐东迁 WANG Ying-jie;XUE Dao-lu;JIAO Lan-yi;LIAO Guo-qiang;QI Dong-qian(Key Laboratory of system integration for high-power AC drive electric locomotives, Zhuzhou 412001, China;School of electrical and power engineering, China University of Mining and Technology, Xuzhou 221008,China;Electro optic explosion proof Technology Co., Ltd.,Yueqing 325600,China)

机构地区：[1]大功率交流传动电力机车系统集成国家重点实验室,湖南株洲412001 [2]中国矿业大学电气与动力工程学院,江苏徐州221008 [3]电光防爆科技股份有限公司,浙江乐清325600

出　　处：《电机与控制学报》2019年第5期93-101,共9页Electric Machines and Control

基　　金：国家重点研发计划资助(2016YFC0600906);徐州市推动科技创新项目(KC18076);中国博士后科学基金(2016M600450)

摘　　要：采用级联U-Cell拓扑相比传统级联H桥拓扑,静止同步补偿器(staticsynchronouscompensator,STATCOM)使用的开关器件更少,损耗更小,设备经济性更高。但级联U-Cell同样存在直流侧电容电压不平衡的问题,严重时可使系统无法运行。针对该问题,首先搭建级联U-Cell拓扑数学模型,详细分析了电容充放电以及实现相内电容电压平衡的工作原理。基于此,提出了一种冗余开关状态轮换与基于开关状态叠加有功电压矢量相结合的控制策略,并将该策略应用推广到任意奇数电平。该策略能够使器件损耗更加均匀,实现了级联U-Cell相内电容电压平衡控制,提高了系统的可靠性。最后分别搭建了基于五电平级联U-Cell拓扑的STATCOM仿真和实验平台,验证了所述理论及控制策略的正确性。Compared with traditional cascade H bridge topology, cascaded U-Cell topology of static synchronous compensator (STATCOM) has few switch devices, low loss and good economic value. However, cascaded U-Cell also exists the problem of unbalanced capacitor voltage, which affects the system reliable operation in severe cases. A mathematical model of cascaded U-Cell is built for this problem, and the principle of capacitor charging and phase-capacitor voltage balance are analyzed in detail. Based on this, a control strategy combining redundant switching states rotation and active voltage vector superimposed by switching state is put forward in the paper, of which is extended to arbitrary odd number level. This strategy can make the device loss more uniform, achieved the balance of the capacitor voltage in the cascade U-Cell, and improve the reliability of the system. Finally, the simulation and experiment platforms of STATCOM based on five-level cascaded U-Cell topology are built to verify the correctness of the theory and control strategy.

关 键 词：级联U-Cell 静止无功补偿器 冗余开关状态 开关状态轮换 有功电压矢量 

分 类 号：TM464[电气工程—电器]