Online Source Impedance Identification in DC Distribution Systems Using the Recursive Extended Least-Squares Method

The dc distribution systems are widely considered in vehicles, ships, aircraft, etc., and may become a reality in future buildings instead of traditional ac systems. To guarantee the stability of source-load interface, the parameters of source impedances are crucial for load controller design. Since the source impedance may vary when the system configuration changes, the online impedance identification is necessary for designing advanced self-stabilizing controllers with “plug-n-play” functionality. Many existing estimation techniques are based on discrete Fourier transform (DFT) of the dynamic response obtained from broadband excitation or impulse injection at the source-load interface, which requires the additional calculation for reconstructing the source impedance transfer function. In this paper, an innovative technique is proposed for parametric identification of source impedance using the recursive extended least-squares (RELS) method. The presented studies validate that the proposed technique yields direct results while having advantages over traditional ac sweep and prior DFT techniques.