On the Convergence of Newton's Method in Power Flow Studies for DC Microgrids

The power flow is a nonlinear problem that requires a Newton's method to be solved in dc microgrids with constant power terminals. This paper presents sufficient conditions for the quadratic convergence of the Newton's method in this type of grids. The classic Newton's method as well as an approximated Newton's method are analyzed in both master-slave and island operation with droop controls. Requirements for the convergence as well as for the existence and uniqueness of the solution starting from voltages close to 1 pu are presented. Computational results complement this theoretical analysis.