模块化多电平变流器的高频谐振分析

首先基于动态向量方法建立模块化多电平变流器（MMC）主电路的10阶状态空间模型,然后根据实际工程建立包含电压电流内环控制、功率外环控制和环流控制在内的MMC控制器状态空间模型。考虑控制环节中存在的采样和计算等延时,采用Pade近似方法对非线性延时环节进行线性化,构建计及延时的MMC换流器与弱电网连接的系统状态空间模型。基于特征值法分析状态空间模型的谐振模态,分析实际MMC-HVDC工程产生高频谐振的机理并分析控制器输入输出延时对稳定性影响关系。通过仿真算例验证该文MMC换流器状态空间模型和高频谐振机理分析的正确性。

HIGH FREQUENCY RESONANCE ANALYSIS OF MODULAR MULTIPLE CONVERTERS

First, based on the dynamic vector method, the 10th-order state space model of the main circuit of the Modular Multilevel Converter （MMC） is established, and then based on the actual project, the inner loop control of voltage and current, the outer power loop control and the circulating current, the state space model of the MMC controller within the control. Considering the sampling and calculation delays in the control link, the Pade approximation method is used to linearize the nonlinear delay link, and the system state space model of the MMC converter and the weak grid connection with the delay is constructed. Based on the eigenvalue method, the resonance mode of the state space model is analyzed, and the mechanism of the actual MMC-HVDC project's high-frequency resonance and the influence of the controller input and output delay on the stability are analyzed. The simulation examples verify the correctness of the MMC converter state-space model and high-frequency resonance mechanism analysis in this paper.