20150028795 | Energy storage apparatus - An energy storage apparatus includes an input unit connected to a solar cell to receive a DC power, a sensing unit for sensing and outputting a voltage of the solar cell, a signal generating unit for generating a periodic signal whose magnitude is periodically changed, a voltage generating unit for variously generating a reference voltage corresponding to the periodic signal, a control signal generating unit for generating a duty control signal by using regions in which the periodic signal has a magnitude lower than or higher than the reference voltage, a charging unit for performing a charging operation by means of an on/off switching operation according to the duty control signal, a battery unit for charging an energy by means of the charging operation of the charging unit, and a main control unit configured to control so that the charging operation is initiated with a reference voltage. | 01-29-2015 |