This paper presents a negative-sequence voltage compensation strategy of a distribution network by using a static synchronous compensator based on modular multilevel converter. Mathematical relations of the static compensator are used to derive small-signal linearised models, in the synchronous reference frame, and to design voltage and current controllers to compensate for unbalanced voltages at the point of common coupling. Moreover, a comprehensive model of the DC bus voltage with a control loop implementation are presented. Furthermore, a notch filter is connected in the feedback path of the DC voltage control loop to eliminate the oscillation in the DC voltage. Digital simulations results, obtained with a 10 MVA / 24 kV MMC-DSTATCOM with 14 submodules per arm, will be used to validate the small-signal linearised mathematical models, and the performance of the designed controllers, during steady-state and faulty grid conditions. In addition experimental results obtained with a small-scale MMC prototype, with 03 submodules per arm, will be presented to demonstrate the feasibility of the compensation strategy proposed here.

提出了一种基于模块化多电平变换器的静态同步补偿器的配电网负序电压补偿策略。静态补偿器的数学关系用于在同步参考框架中导出小信号线性化模型，并设计电压和电流控制器以补偿公共耦合点处的不平衡电压。此外，提出了具有控制回路实现的直流母线电压的综合模型。此外，陷波滤波器连接在直流电压控制回路的反馈路径中，以消除直流电压的振荡。使用10 MVA / 24 kV MMC-DSTATCOM（每臂具有14个子模块）获得的数字仿真结果将用于验证小信号线性化数学模型，以及稳态和故障电网条件下设计的控制器的性能。此外，还将展示使用每臂具有03个子模块的小型MMC原型获得的实验结果，以证明此处提出的补偿策略的可行性。