Stability Analysis for VSR-Based DC Distribution Network Using Singular Perturbation Theory

This paper addresses the stability analysis of DC distribution networks with voltage source rectifiers (VSRs) and constant power loads (CPLs). Existing stability criteria for DC networks often rely on simplified models neglecting source converter controller dynamics, limiting their applicability in practical controller design. To overcome this, a singular perturbation-based framework is proposed to derive analytical stability conditions for closed-loop DC distribution network systems. By decomposing the high-dimensional Jacobian matrix into two structured low-dimensional matrices, tractable stability criteria are established using properties of Karush-Kuhn-Tucker (KKT) matrices. Sufficient stability conditions for local stability of a VSR-based DC distribution network are derived without requiring global VSR information, while a robust stability criterion dependent solely on maximum load data is developed to handle uncertainties. These results provide explicit design guidelines to enhance robustness and reduce computational complexity in stability analysis. Simulations validate the effectiveness of the proposed approach. © 2025 IEEE.