低容值级联对称半桥型静止同步补偿器  

Low Capacitance STATCOM Based on Cascaded Symmetrical Half-bridge Converter

作　　者：王顺亮 李金铭 张芮[1] 马俊鹏 廖鑫 刘天琪[1] WANG Shunliang;LI Jinming;ZHANG Rui;MA Junpeng;LIAO Xin;LIU Tianqi(College of Electrical Engineering,Sichuan University,Chengdu 610065,Sichuan Province,China)

机构地区：[1]四川大学电气工程学院,四川省成都市610065

出　　处：《电网技术》2024年第8期3493-3501,I0148,I0149,共11页Power System Technology

基　　金：四川省自然科学基金项目(2023NSFSC0301)。

摘　　要：级联H桥型的静止同步补偿器(static synchronous compensator,STATCOM)具有模块化程度高、可靠性高、输出谐波特性好等优点,受限于直流电容电压波动要求,子模块需要采用大容值电容,阻碍了变流器的高功率密度化。为降低STATCOM的成本及体积,该文提出一种低容值的级联对称半桥型STATCOM,可较大程度减小子模块电容值及开关数量。通过分析低电容值条件下直流侧电容电压波动规律,揭示了直流侧电容值、电容电压波动大小与输出无功电流的关系,提出直流侧电容选取方法。为最大化利用直流电压,研究直流侧电压参考取值原则,实现对电压波动的峰、谷值控制,提出直流总电压控制及子模块电容电压均衡控制策略。分析了容性与感性无功模式下STATCOM的运行范围,揭示运行范围与电容电压波动上限的关系。最后,通过仿真与实验验证了电容值降低方法与控制策略的正确性及有效性。The cascaded H-bridge type static synchronous compensator(STATCOM)is known for its high modularity,reliability,and excellent output harmonic characteristics.However,it is limited by the voltage fluctuation requirements of the DC capacitor,which necessitates the use of large capacitance capacitors for the submodules,thereby hindering the achievement of high-power density in the converter.To reduce the cost and size of the STATCOM,this paper presents a novel low capacitance cascaded symmetrical half-bridge STATCOM.This solution significantly reduces the capacitance value of the submodules and the number of switches.By investigating the characteristics of DC-side capacitor voltage fluctuation under low capacitance conditions,an analytical relationship between the capacitance value,voltage fluctuation magnitude and output reactive current is established.Furthermore,a method for selecting the DC-side capacitor is proposed to maximize the utilization of the DC voltage.A control strategy for regulating the peak and valley values of the voltage fluctuation as well as ensuring the control of DC total voltage and submodule capacitor voltage equalization is developed.The operating range of the STATCOM in capacitive and inductive reactive modes is analyzed,establishing the correlation between the operating range and the upper limit of capacitor voltage fluctuation.Finally,Simulation and experimental results are provided to validate the correctness and feasibility of the proposed capacitance reduction method and control strategy.

关 键 词：对称半桥 静止同步补偿器 低容值 直流侧电压控制 

分 类 号：TM721[电气工程—电力系统及自动化]