适用于交直流混联电网的CH-MMC电磁暂态快速仿真模型

Efficient electromagnetic transient simulation model of CH-MMC for AC-DC hybrid grid

针对交直流混联电网中半桥和全桥子模块混合型模块化多电平换流器(CH-MMC)详细模型存在电磁暂态仿真计算量大、耗时长等问题,提出一种基于子模块电容电量均分的CH-MMC快速仿真模型。依次分析了半桥和全桥子模块的正常运行和闭锁状态等效电路,基于半桥和全桥阀段在不同状态下投入和闭锁的子模块数推导出半桥和全桥阀段的等效电路以及CH-MMC快速仿真模型;在该模型基础上提出一种阀段间均压控制策略并实现三段式充电启动过程,进而梳理了该模型的阀级控制流程。在MATLAB/Simulink中与详细模型进行对比,验证了所提CH-MMC快速仿真模型的正确性和快速性。

Aiming at the large-scale and long-time calculation existing in the electromagnetic transient simulation for the detailed model of CH-MMC(Cell-Hybrid Modular Multilevel Converter) applied in AC-DC hybrid grid, an efficient simulation model of CH-MMC based on charge equalization of submodule capacitors is proposed. The equivalent circuits of the half-bridge and full-bridge submodules in normal and blocking states are analyzed respectively. Based on the numbers of half-bridge and full-bridge submodules in normal and blocking states, the equivalent circuits of half-bridge and full-bridge valve segments and the efficient simulation model of CH-MMC are derived. Furthermore, a voltage balancing method is proposed based on the proposed model, and the three-stage charging strategy is realized. Compared with the detailed model based on MATLAB/Simulink, accuracy and efficiency of the proposed model are validated by simulative results.