NOVELTY - The system has a wind power generation unit for converting wind energy into electrical energy and outputting the electrical energy, and a wind power generation controlling unit for controlling electrical energy output from the wind power generation unit. A capacitor and a battery store the electrical energy controlled by the wind power generation controlling unit. The wind power generation controlling unit includes a direct current (DC)-DC converter monitoring the wind power generation unit and the capacitor to selectively boost the electrical energy output from the wind power generation unit.    USE - Wind power generation system.    ADVANTAGE - The DC-DC converter is configured in a two-stage form including two converters such that the DC-DC converter can flexibly cope with an electrical energy state i.e. power or voltage state, of the capacitor and the electrical energy output from the wind power generation unit to maximize boosting efficiency. The wind power generation controlling unit includes a capacitor overcharge preventing unit monitoring the capacitor to interrupt the electrical energy supplied from the wind power generation unit to the capacitor, thus preventing overcharge of the capacitor. The system allows the battery and the DC-DC converter controlling the electrical energy supplied to the battery to be monitored by a battery monitoring unit in a battery controlling unit, so that the DC-DC converter of the battery controlling unit improves lifespan of the battery. The system can stably supply the electrical energy generated by wind power generation to the battery through the capacitor. The DC-DC converter boosts voltage output from the wind power generation unit at lower wind speed and another converter boosts the voltage output from the wind power generation unit at high wind speed so as to improve storage characteristics of the electrical energy at the low wind speed.    DETAILED DESCRIPTION - The DC-DC converter is a constant current-type boost converter. An INDEPENDENT CLAIM is also included for a method for controlling a wind power generation system.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of a wind power generation controlling unit.