This paper presents state space representation and a method of the automatic development of the small signal model of dc distribution network. The model can represent the dynamics of the converter-interfaced wind, photovoltaic generation units and energy storage system around the steady-state operating point. The presented model considers the voltages crossing capacitors, the currents through inductors, the control variables as state variables, and the variations of the wind speed, irradiance solar, loads as the control input. The whole state space equations are developed automatically. A detailed small-signal mathematical model is derived automatically by using the stamping method to analyze the small-signal stability of the system. Time-domain simulation is used to verify the method. The effects of system and controller parameters on the system performance are analyzed.