Impedance Modeling of a Three-Phase Dual-Active Bridge with a Supercapacitor Connected to the Primary Side

Abstract:
With increasing complexity of control strategies and system architectures, accurate stability analysis for DC microgrids becomes more relevant. In this paper, an impedance model for a dual-active bridge (DAB) connected to a supercapacitor module is derived. The primary feature of this model is the consideration of the supercapacitor’s equivalent series resistance (ESR). The model is validated using electromagnetic transient (EMT) simulations and then used to analyze the stability of a DC microgrid consisting of a DAB and a constant power load (CPL). The impact of the supercapacitor’s ESR and the addition of droop control on the stability of the system is examined.