【目的】在构网型多变流器系统仿真中，传统LC等效模型存在精度不足、暂态响应误差较大等问题，难以适应高频开关特性，尤其在亚微秒级仿真步长下无法准确表征开关暂态过程。针对上述问题，本文提出了一种基于状态矩阵的构网型多变流器系统高精度建模方法。【方法】首先，建立构网型虚拟同步发电机控制下的变流器开关元件离散化模型，通过离散电路联合理想开关特性确定待定参数，构建基于LC等效电路的广义恒导纳开关(FAS)模型；其次，基于构网型多变流器耦合特性，推导单变流器状态矩阵向多变流器系统的拓展方法，建立系统级状态空间方程，准确表征多变流器间的动态交互过程；最后，基于PSCAD/EMTDC平台搭建构网型多变流器系统仿真模型，将所提FAS模型与PSCAD理想模型及传统LC等效模型进行对比。【结果】仿真结果表明，所提FAS模型仿真结果更加贴近PSCAD理想模型，有效降低了亚微秒级仿真步长下的功率损耗，在维持系统稳定性的同时，提高了系统仿真精度及效率。【结论】所提FAS模型在亚微秒级仿真步长下具有良好的适用性和稳定性。

[Objective] In the simulation of grid-forming multi-converter systems, traditional LC equivalent model exhibits insufficient accuracy and significant transient response errors, rendering them struggle to accommodate high-frequency switching characteristics, particularly failing to accurately represent switching transient processes at sub-microsecond simulation time step. To resolve the above challenges, a high-precision modeling method for grid-forming multi-converter system based on state matrix is proposed. [Methods] Firstly, a discretized model for converter switching components under grid-forming virtual synchronous generator control was established, where undetermined parameters were determined by combining discrete circuit with ideal switching characteristic, thereby constructing a generalized fixed-admittance switching (FAS) model based on LC equivalent circuits. Secondly, based on the coupling characteristics of grid-forming multi-converter, an extension method from the single converter state matrix to the multi-converter system was derived, and system-level state-space equations were formulated to efficiently characterize dynamic interactions among converters. Finally, a grid-forming multi-converter system simulation model was established based on the PSCAD/EMTDC platform, and compared the proposed FAS model with the PSCAD ideal model and traditional LC equivalent model. [Results] The simulation results showed that the simulation results of proposed FAS model were closer to the PSCAD ideal model, which effectively reduced the power loss under the sub-microsecond simulation time step and improved the system simulation accuracy and efficiency while maintaining the system stability. [Conclusion] The proposed FAS model exhibits excellent applicability and stability under sub-microsecond simulation time step.

国家电网有限公司总部科技项目(5400-202318547A-3-2-ZN)