A generalized DQ impedance model of ATRU system

Three-phase ac systems can be transferred into dq axis, where stability analysis becomes much simpler. In order to apply the stability criterion in AC system, an equivalent DQ admittance model for the ATRU system has been developed in this paper, based on the ABC impedance model in paper [1]. Compared to the literature work, this model has two better features: (1) it is valid in a wide frequency range, which is from below fundamental frequency to high number times of fundamental frequency; (2) it considers the effect of the ac line impedance and output dc impedance. At different circuit parameters, including the extreme cases, the analytical modeling results and the numerical simulation results present excellent agreement, which demonstrates the accuracy of the analytical model.