Distributed generation system is a reliable, economical and efficient electrification option that interconnects different energy sources. Small and local distribution generation system including storage systems and load is defined as a microgrid. This paper presents an energy management strategy to supervise the power flows in a stand-alone DC microgrid power generation plant. The plant is composed of: a wind turbine, a photovoltaic generator, battery storage system and diesel generator combined with a supercapacitor. The DC microgrid is designed and modeled using Matlab/ Simulink/ SimPowSysâ„¢ environment. The supercapacitor is utilized to cover the deficiency of power shortage during the start-up of the diesel generator. It is also utilized to compensate the limitations on the charging/discharging current of battery. The power balance of the suggested system is the main objective of the proposed management strategy. Some performance indexes are considered: the frequency deviation, the stability of the DC bus voltage and the AC voltage total harmonic distortion. The performances of the proposed strategy are evaluated by simulation in different operating conditions. Simulation results confirm the effectiveness of the proposed power management strategy.