The direct-quadrature (DQ) model, mirror-frequency impedance (MFI) model, and harmonic state-space (HSS) model are three main modeling methods for single-phase power electronic converter systems. These models are established under three different frameworks: the dq-frame, the mirror-frequency frame, and the extended harmonic domain frame. The purpose of this article is to demonstrate how to create a unified modeling framework and to provide an unambiguous relationship between the impedances in these three domains. The unified model framework facilitates flexible and scalable modeling by making different models to be easily interconnected with other systems. In addition, to simplify the stability analysis and impedance measurement process, the three modeling methods are reduced to first-order single-input and single-output (SISO) equivalent models, respectively, based on the model reduction technique. Finally, the impedance measurement and stability analysis results of electric multiple units (EMUs) accessed vehicle-grid system demonstrate the accuracy of the conversion and SISO equivalence technique.

中文翻译：

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动车组单相换流器阻抗模型的换算及SISO等价

直接正交 (DQ) 模型、镜像频率阻抗 (MFI) 模型和谐波状态空间 (HSS) 模型是单相电力电子转换器系统的三种主要建模方法。这些模型是在三个不同的框架下建立的：dq 框架、镜像频率框架和扩展谐波域框架。本文的目的是演示如何创建统一的建模框架并提供这三个域中阻抗之间的明确关系。统一的模型框架使不同的模型可以轻松地与其他系统互连，从而促进灵活和可扩展的建模。此外，为简化稳定性分析和阻抗测量过程，将三种建模方法简化为一阶单输入单输出（SISO）等效模型，分别基于模型缩减技术。最后，动车组（EMUs）接入的车辆-电网系统的阻抗测量和稳定性分析结果证明了转换和SISO等值技术的准确性。