分频输电系统模块化多电平矩阵变换器谐波特性分析  

Harmonic characteristics analysis of modular multilevel matrix converter for fractional frequency transmission system

作　　者：孙玉巍[1] 常静恬 付超[1] 郭锋 周靖皓 高本锋[1] SUN Yuwei;CHANG Jingtian;FU Chao;GUO Feng;ZHOU Jinghao;GAO Benfeng(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(North China Electric Power University),Baoding 071003,China;State Grid Taizhou Power Supply Company of Zhejiang Electric Power Co.,Ltd.,Taizhou 318000,China;State Grid Zhejiang Electric Power Co.,Ltd.,Hangzhou 310007,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),河北保定071003 [2]国网浙江省电力有限公司台州供电公司,浙江台州318000 [3]国网浙江省电力有限公司,浙江杭州310007

出　　处：《电力工程技术》2022年第5期21-30,84,共11页Electric Power Engineering Technology

基　　金：河北省自然科学基金资助项目(E2019502172)。

摘　　要：模块化多电平矩阵变换器(M3C)是构建分频输电系统(FFTS)的核心装备,但是M3C在进行交-交变换时,会导致两侧不同频率交流系统电气量在M3C内直接耦合,引起系统复杂的谐波分布。为分析M3C谐波特性,首先基于M3C工作原理推导得到子模块电容纹波电压解析式,在此基础上推导9个桥臂考虑子模块电容电压全部4种频率分量耦合的桥臂谐波电流解析式,进而分析多种频率桥臂谐波电流与系统电流的关系以及影响纹波电压/谐波电流幅值的关键因素。结果表明,在稳态下,分频侧频率ω_(1)和工频侧频率ω_(2)的电流分量以正序基波电流性质流入对应系统;频率为3ω_(1)和3ω_(2)的电流分量以零序谐波电流性质流入两侧交流系统;其他频率谐波分量在变换器内部环流。文中针对M3C提出一种零序电流抑制控制策略,并在Matlab/Simulink中进行仿真,验证了谐波理论分析的准确性以及控制策略的有效性。The modular multilevel matrix converter(M3C)is the core equipment for fractional frequency transmission system(FFTS).The AC-AC conversion of M3C leads to direct coupling of the ac electrical quantities at different frequencies,causing complex harmonic distribution.In order to analyze the harmonic characteristics of the M3C,the analytical expression of the sub-module capacitor ripple voltage is derived based on the operating principle of M3C at first.On this basis,the analytical formulas of the nine bridge arms currents harmonics are derived,taking into account the coupling of all four frequency components of the capacitor voltage.The relationships between the multi-frequency harmonic currents of bridge arm and the system currents on two sides are analyzed,as well as the key factors affecting the amplitudes of ripple voltage/harmonic current are discussed.The results show that in steady-state,the currents at frequencies ω_(1) and ω_(2) flow into the ac systems as the positive-sequence fundamental currents;the currents at frequencies 3ω_(1) and 3ω_(2) flow into the ac system as the zero-sequence components;the remaining harmonics are circulated in the converter.A zero-sequence current mitigation control strategy for the M3C is proposed.The accuracy of the theoretical harmonic analysis and the effectiveness of the control strategy are verified by simulations in Matlab/Simulink.

关 键 词：分频输电系统(FFTS) 模块化多电平矩阵变换器(M3C) 谐波分析 频率耦合 电容纹波电压 桥臂电流 

分 类 号：TM46[电气工程—电器]