采用非线性无源理论的MMC-MG并网电流控制  

Grid-connected current control for MMC-MG adopting nonlinear passive theory

作　　者：王兴贵[1] 王海亮[1] 薛晟 李晓英[1] WANG Xing-gui;WANG Hai-liang;XUE Sheng;LI Xiao-ying(School of Electrical Engineering and Information Engineering,Lanzhou University of Technology,Lanzhou Gansu 730050,China)

机构地区：[1]兰州理工大学电气工程与信息工程学院,甘肃兰州730050

出　　处：《控制理论与应用》2022年第8期1541-1550,共10页Control Theory & Applications

基　　金：国家自然科学基金项目(51967011);甘肃省自然科学基金项目(21JR7RA207)资助.

摘　　要：针对MMC半桥串联结构微电网(modular multilevelconvertermicrogrids,MMC–MG)并网电流控制中,采用传统PI控制方法时其动态性能较差的问题,提出一种利用无源控制理论的电流控制策略.首先,阐述了系统的拓扑结构,并建立了其欧拉–拉格朗日数学模型.然后,通过选取系统的状态变量,设置误差能量函数及需注入的阻尼项,以得到无源控制律;并依据该控制律设计无源电流控制器.此外,通过观察采用不同阻尼值时控制器的稳定性、电流谐波特性、幅频和相频特性曲线,进而得到最佳的阻尼参数;最后,由系统的并网仿真模型验证所提无源电流控制的有效性.结果表明,与传统PI控制相比,阻尼注入无源控制方法能在不同运行工况下实现对电流和功率参考值的快速跟踪.同时,具有良好的谐波特性和稳定性.Aiming at the poor dynamic performance of traditional PI control method in grid-connected current control of the modular multilevel converter microgrids,a current control strategy adopting passive control theory is proposed.Firstly,the topological structure of the system is described,and its Euler-Lagrange mathematical model is established.Then,the passive control law is obtained by selecting the state variables of the system,setting the error energy function and the damping term to be injected.And the passivity-based current controller is designed on the passive control law.In addition,the optimal damping parameters are obtained by observing the stability,current harmonic characteristics,amplitude-frequency and phase-frequency characteristic curve of the controller with different damping values.Finally,the effectiveness of the proposed passivity-based current control is validated with simulations using grid-connected models of the system.The results show that the passivity-based control method of damping injection can quickly track the current and power reference values under different operating conditions compared with the traditional PI control.And it has good harmonic characteristics and stability.

关 键 词：微电网 电流控制 动态性能 无源控制 PI控制 

分 类 号：TM73[电气工程—电力系统及自动化]