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针对模块化多电平变流器(Modular Multilevel Converter,MMC)的多变量、强非线性特性,从能量耗散和结构简洁的角度出发,建立MMC动态数学模型,直接在a-b-c静止坐标系下推导双线性Lagrangian方程,分析系统严格无源特性.以均衡子模块电容电压为目标设计能量函数,结合PI控制简单架构,提出新型的无源性PI控制方法,使系统在满足全局渐进稳定的前提下,实现期望轨迹的快速跟踪.搭建MMC并网逆变仿真模型,仿真结果表明所提出的方法具有响应快速、稳定性高、鲁棒性强的特点.“,”Modular multi-level converter (MMC) has such characteristics as multi-variable and strongly nonlinear.From the perspective of energy dissipation and simple structure,the bilinear Lagrangian equation in a-b-c synchronous reference frame is developed directly based on the dynamic mathematical model of MMC to strictly analyze passive features of the system.Then energy function for balancing capacitor voltage is designed.By combining the simple architecture of PI control,a novel passivity-based PI control method is proposed to ensure that the desired fast trajectory tracking can be realized under the premise of global asymptotic stability.A simulation model of MMC grid-connected system is built up by using MATLAB/SIMULINK,and the simulation results show that the proposed control method has such advantages as quick response,high stability and strong robustness.