Large-Signal Stability Analysis of DC Power System With Shunt Active Damper

This paper proposes a large-signal stabilization method for the dc power system with a constant power load (CPL), which is detrimental to system stability due to its negative incremental resistance (NIR). The proposed method utilizes a shunt active damper at the point of common coupling of the dc bus and controls it as a parallel set of a virtual capacitor, virtual inductor, and resistor. The Takagi–Sugeno fuzzy model is employed with the Lyapunov stability theorem to verify the asymptotic stability of the system and to estimate the region of asymptotic stability. Improvements on the dc-bus voltage stability are evaluated based on dc-bus voltage deviation or dc-bus capacitance reduction. The performance of the proposed shunt active damper is verified by simulation and experimental results.