Due to the specificity of continuous casting production, the application of ac/ac MMC structure in induction heating power supply requires the realization of frequency conversion from grid AC to low and medium single-phase AC, which makes the conventional modeling methods inappropriate. In this article, an HSS-based reduced order impedance model is proposed. Firstly, due to the complexity of the internal harmonics, the harmonic attenuation of the internal signals is calculated quantitatively by analyzing the three-dimensional signal-flow graph and then the harmonic frequencies are truncated, which provide a basis for model simplification. Furthermore, to precisely describe the amplitude-phase characteristics of the ac/ac MMC under different output frequencies, the harmonic state space modeling method is improved by combining the double Fourier integral transform. Finally, the correctness of the frequency analysis and the accuracy of the reduced order model are verified.

中文翻译：

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用于中间包加热的 AC/AC 模块化多电平转炉的双基频 HSS 降阶阻抗建模


由于连铸生产的特殊性，ac/ac MMC结构在感应加热电源中的应用需要实现从电网交流到中低单相交流的变频，这使得传统的建模方法不再适用。在本文中，提出了一种基于HSS的降阶阻抗模型。首先，由于内部谐波的复杂性，通过分析三维信号流图定量计算内部信号的谐波衰减，然后截断谐波频率，为模型简化提供基础。此外，为了精确描述不同输出频率下ac/ac MMC的幅相特性，结合双傅里叶积分变换改进了谐波状态空间建模方法。最后验证了频率分析的正确性和降阶模型的准确性。