Patent ID: 7148586
Filing Date: 2006-12-12
Classification: H02J

Abstract:
1. An uninterruptible power supply system (UPS, comprising: arectifier for rectifying commercial alternating currant (AC) power from an input terminal and converting the AC power into direct current (DC) power; a charger for charging a battery with the DC power; the battery for providing the DC power; a DC-DC converter for boosting and/or dropping the DC power inputted from the battery by a predetermined level of the AC power; a D-class amplifier for receiving the DC power from the DC-DC converter and outputting a sine waveform power signal in response to a waveform control signal; a sine waveform controlling a sine waveform generation operation of the D-class amplifier; and a switching unit for switching the commercial AC power from the input terminal to a load in a normal mode, and switching the sine waveform power signal from the D-class amplifier to the load when an error of the commercial AC power is detected; wherein the D-class amplifier comprises a bridge circuit for power conversion, the bridge circuit comprising; a first inductance device (L a third inductance device (L a first capacitance device (C a second capacitance device (C two load output terminals (X and Y) connected to the first and second node (A and B) respectively, wherein the sine waveform controller performs a control operation so that a difference between a turn-on time of one pair of switching devices (SW wherein the sine waveform controller adjusts the turn-on time difference in each switching period, and performs a control operation so that the voltage outputted through the output terminal (X or Y) corresponds to sine waveform power equal to the commercial AC power.