To effectively capture interactions of large-scale ac-dc systems integrating line commutated converter (LCC) and modular multilevel converter (MMC) based multiterminal dc grids, a numerically accurate and efficient simulation method is desirable. To achieve this objective, a cosimulation method is proposed in this article, where the target system is decoupled into the shifted-frequency phasor (SFP) subsystem, the dynamic phasor (DP) subsystem, and electromagnetic transient (EMT) subsystem, respectively. The MMCs are included in the SFP subsystem and implemented on massively paralleled graphics processing units (GPUs). Thus, the simulation efficiency is greatly improved by adopting a much larger time step, the model order reduction technique, and GPU acceleration. The LCCs are represented by DPs and are included in the DP subsystem. The majority of ac grids are covered in the EMT subsystem. Further, the interactions between SFP and EMT subsystems are reflected by the proposed multidomain transmission line model, which can produce instantaneous and phasor values simultaneously. The interface model between DP and EMT subsystems is modeled as a special controlled voltage and current circuit. Finally, the overall cosimulation method is realized by the respective SFP/DP and EMT models, among which their interactions are reflected by the proposed interface models and the time sequences of simulations. The performance of the proposed method has been fully validated on a practical large-scale ac-dc system.

中文翻译：

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集成 CPU__PU 上混合 LCC-MMC 直流电网的移频/动态相量和电磁暂态模型的协同仿真


为了有效地捕获基于多端直流电网的集成线路换向转换器（LCC）和模块化多电平转换器（MMC）的大型交直流系统的相互作用，需要一种数值精确且高效的仿真方法。为了实现这一目标，本文提出了一种协同仿真方法，将目标系统分别解耦为移频相量（SFP）子系统、动态相量（DP）子系统和电磁暂态（EMT）子系统。 MMC 包含在 SFP 子系统中，并在大规模并行图形处理单元 (GPU) 上实现。因此，通过采用更大的时间步长、模型降阶技术和GPU加速，大大提高了仿真效率。 LCC 由 DP 表示并包含在 DP 子系统中。 EMT 子系统覆盖了大部分交流电网。此外，所提出的多域传输线模型反映了SFP和EMT子系统之间的相互作用，该模型可以同时产生瞬时值和相量值。 DP和EMT子系统之间的接口模型被建模为特殊的受控电压和电流电路。最后，通过各自的SFP/DP和EMT模型实现了整体协同仿真方法，它们之间的相互作用通过所提出的接口模型和仿真时间序列来反映。该方法的性能已在实际的大规模交直流系统上得到充分验证。