桥臂不对称情形下MMC无源性PI控制方法  

Passivity-Based PI Control Method of MMC with Asymmetric Bridge Arms

作　　者：陈程 薛花 扈曾辉 王育飞 CHEN Cheng;XUE Hua;HU Zenghui;WANG Yufei(Electric Power Engineering,Shanghai University of Electric Power,Shanghai 200090,China;China Mobile Communications Group Shandong Co.,Ltd.,Jining Branch,Jining 272000,China)

机构地区：[1]上海电力大学电气工程学院,上海200090 [2]中国移动通信集团山东有限公司济宁分公司,山东济宁272000

出　　处：《中国电力》2023年第7期107-116,124,共11页Electric Power

基　　金：上海市科委地方能力建设项目(面向新型电力系统的规模化储能电站应用关键技术研究,22010501400)。

摘　　要：考虑模块化多电平变换器(modular multilevel converter,MMC)桥臂不对称情形,针对环流基频分量不对称引起的dq解耦变换误差问题,提出基于双线性模型的无源性PI控制方法,实现故障相电容电压保持稳定、不对称环流分量的准确抑制、三相并网电流的平衡输出。在abc坐标系下,建立桥臂不对称情形下MMC双线性模型,完成非线性系统控制变量随状态变量同步变化的线性化转换,简化控制器设计,避免dq解耦变换引入的控制误差。从系统全局能量耗散特性出发,设计形式简单的无源性PI控制器,实现子模块电容电压纹波快速抑制,消除桥臂电流不对称性,同时确保闭环控制系统全局渐近稳定运行。基于Matlab的仿真结果验证了所提控制策略能够有效抑制MMC桥臂不对称的不利影响,具有响应快速、稳定性好、鲁棒性强的特点。Considering asymmetric bridge arms of modular multilevel converter(MMC),a passivity-based PI control method based on the bilinear model is proposed to address the dq decoupling transformation errors caused by the fundamental frequency component asymmetry of circulating currents,,which can achieve stable fault phase capacitor voltage,accurate suppression of asymmetric circulating current components and balanced output of three-phase grid-connected currents.Firstly the MMC bilinear model under the condition of asymmetric bridge arm is established in the abc coordinate.Then the linear transformation of the nonlinear system is conducted,in which the control variables are adjusted synchronously with the state variables.In this way the controller design is simplified and the control errors introduced by the dq decoupling transformation are diminished.Based on the global energy dissipation characteristics of the system,a simple passivity-based PI controller is designed to quickly suppress the submodule capacitor voltage ripple,eliminate the current asymmetry of the bridge arm,and hence ensure the global asymptotically stable operation of the closed-loop control system.The simulation results based on MATLAB has verified that the proposed control method can effectively suppress the adverse effects from the asymmetric bridge arm,and exhibits its capability of fast response,strong stability and high robustness.

关 键 词：模块化多电平变换器 桥臂不对称 无源性PI控制 双线性模型 

分 类 号：TM46[电气工程—电器] TP273[自动化与计算机技术—检测技术与自动化装置]