一种增加辅助子模块的MMC改进混合调制控制策略  

Improved Hybrid Modulation Strategy for MMC with Auxiliary Sub-modules

作　　者：杨光源[1] 周诗嘉 彭光强[1] 武霁阳 辛清明 许树楷 YANG Guangyuan;ZHOU Shijia;PENG Guangqiang;WU Jiyang;XIN Qingming;XU Shukai(Maintenance&Test Center,China Southern Power Grid EHV Power Transmission Company,Guangzhou 510663,China;China Southern Power Grid Research Institute Co.,Ltd.,Guangzhou 510080,China)

机构地区：[1]中国南方电网超高压输电公司检修试验中心,广州510663 [2]南方电网科学研究院有限责任公司,广州510080

出　　处：《电源学报》2024年第1期74-82,共9页Journal of Power Supply

基　　金：南方电网科技资助项目(ZBKJXM20180560);国家自然科学基金资助项目(51977070)。

摘　　要：传统的最近电平逼近调制NLM(nearest level modulation)具有控制简单,开关频率低的显著优势,但在输出电平数较少时,采用NLM调制的模块化多电平换流器MMC(modular multilevel converter)输出波形谐波畸变率较大。在传统三相六桥臂MMC拓扑的各桥臂中增加1个全桥结构的辅助子模块,控制该辅助子模块的电容电压为半桥子模块的一半。针对该MMC拓扑,提出了一种改进的混合调制策略,该混合调制策略可以实现半桥和辅助子模块的平衡控制。在降低MMC交流侧输出电流的谐波畸变率同时,还可以降低全桥子模块的开关频率和系统损耗。在Matlab/Simulink中搭建了详细的仿真模型,仿真结果验证了所提MMC拓扑和改进混合调制策略的有效性。The traditional nearest level modulation(NLM)has advantages of simple control and low switching frequency.However,when the number of output levels is small,the harmonic distortion rate of output waveform from a modular multilevel converter(MMC)under the NLM modulation will be large.In this paper,a full-bridge auxiliary sub-module is added to each arm of the traditional three-phase six-leg MMC topology,and the capacitance voltage of the auxiliary sub-module is half of that of the half-bridge sub-module.Aimed at this MMC topology,an improved hybrid modulation strategy is proposed,which can realize the balance control of half-bridge and auxiliary sub-module,reduce the harmonic distortion rate of MMC AC-side output current,and reduce the switching frequency and system loss of the full-bridge sub-module.A detailed simulation model is built in MATLAB/Simulink,and simulation results verify the effectiveness of the proposed MMC topology and the improved hybrid modulation strategy.

关 键 词：模块化多电平变流器 混合调制 平衡控制 降频控制 

分 类 号：TM46[电气工程—电器]