模块化多电平换流器阀基主动均压控制策略研究  

Research on the Valve-based Active Average Voltage Control Strategy for Modular Multilevel Converter

作　　者：许建中[1] 郭裕群 何智鹏 徐莹[1] 赵成勇[1] XU Jianzhong GUO Yuqun HE Zhipeng XU Ying ZHAO Chengyong(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China Electric Power Research Institute, China Southern Power Grid Co., Ltd., Guangzhou 510080, China)

机构地区：[1]华北电力大学新能源电力系统国家重点实验室,北京102206 [2]南方电网科学研究院有限责任公司,广东广州510080

出　　处：《华北电力大学学报（自然科学版）》2017年第2期47-54,共8页Journal of North China Electric Power University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51177042)

摘　　要：模块化多电平换流器阀臂中子模块IGBT的平均开关频率和电容电压纹波幅值具有相互耦合的特性,如何在保证纹波幅值不超标的情况下精确定量控制IGBT的平均开关频率具有重要的理论和工程意义。基于此提出一种MMC阀基主动控制策略。首先,基于一种改进的电容均压排序算法和其子模块电容电压纹波幅值与IGBT平均开关频率的数学关系,为基于PI控制器的主动均压策略提供输出阈值的设计准则;其次,设计了一种在线测量IGBT平均开关频率的模块,可以实现开关频率的划窗式动态测量;进而,提出了定量控制IGBT平均开关频率的闭环控制器。最后,为证明所提出频率控制方法的有效性,在PSCAD/EMTDC中搭建了双端401电平MMC-HVDC系统分别针对稳态、潮流翻转以及严重交、直流故障情况验证了所提出的MMC阀基主动均压控制策略鲁棒性和工程适用性。Average switching frequency of the IGBT and the amplitude of the sub-module capacitor voltage ripples in the arm of a modular multilevel converter （ MMC ） are in an inter-coupling relationship. Therefore, it is of theoretical and engineering significance to come up with a method to control the IGBT average switching frequency precisely with the amplitude of capacitor voltage ripples under its limitation. The valve-based active control strategy of the MMC is proposed. At first, on the basis of an improved capacitor voltage sorting algorithm and the mathematical relationship between the amplitude of the capacitor voltages of sub-modules and the IGBT average switching frequency, the design criteria of output threshold value of active average voltage strategy with PI controller can be obtained. Then, a module for on-line measurement of the IGBT average switching frequency is designed, which makes it possible to take the row window-type dynamic measurement of the switching frequency. Besides, a closed-loop PI controller for the quantitative control of the IGBT average switching frequency is proposed. Finally, in order to prove the effectiveness of the proposed frequency controlling method, a 401 -level two-terminal MMC-HVDC system is built in PSCAD/EMTDC. The simulations under the steady state, power reversal operation and the fault operation are carried out respectively and the simula- tion results proved the robustness and engineering applicability of the proposed valve-based active control strategy.

关 键 词：模块化多电平换流器 新型排序均压算法 IGBT平均开关频率 子模块电容电压纹波幅值 PI控制器 

分 类 号：TM46[电气工程—电器]