Parameter Design of DCMG System Under Large Signal Stability and Static Voltage Constraints

DC microgrid (DCMG) is characterized by a high degree of power electronics, low system inertia, and CPL (CPL) with a negative damping feature. Its system-level transient stability is of great concern. The stability of a DCMG system is affected by many factors, such as component parameters, load types, converter control methods, etc. To analyze the system-level stability of the DCMG, the constraints of large signal stability of the DCMG based on droop control are derived by using the Lyapunov direct method. Based on this conclusion, the influence of system parameters on large signal stability and voltage deviation of the DCMG is revealed, and the optional range of filter element parameters and droop coefficient under the stability and voltage constraints is proposed. The parameter selection work involves two evaluation indicators, system stability, and voltage deviation. This article uses the variable weight coefficient method to normalize these two indicators into a comprehensive evaluation index, and the appropriate droop coefficient is selected based on the optimal comprehensive evaluation index. The work of this article has reference values for the parameter design of the DCMG system components and the selection of the droop coefficient.