We study the tangential interpolation problem for a passive transfer function in standard state-space form. We derive new interpolation conditions based on the computation of a deflating subspace associated with a selection of spectral zeros of a parameterized para-Hermitian transfer function. We show that this technique improves the robustness of the low order model and that it can also be applied to non-passive systems, provided they have sufficiently many spectral zeros in the open right half plane. We analyze the accuracy needed for the computation of the deflating subspace, in order to still have a passive lower order model and we derive a novel selection procedure of spectral zeros in order to obtain low order models with a small approximation error.

翻译：我们研究了标准状态空间形式下无源传递函数的切向插值问题。基于参数化共轭对称传递函数谱零点选取的收缩子空间计算，推导了新的插值条件。实验表明，该技术能提升低阶模型的鲁棒性，且可应用于非无源系统（前提是其在开右半平面具有足够多的谱零点）。为保障降阶模型的无源性，分析了收缩子空间计算所需精度，并提出了一种新的谱零点选取策略，以获得近似误差较小的低阶模型。