Patent ID: 8493696
Filing Date: 2013-07-23
Classification: H02J

Abstract:
1. An uninterruptible power supply that converts a DC voltage to an AC voltage and that supplies the AC voltage to a load device, comprising: a control unit configured to perform a failure determination based on an instantaneous value provided by an internal voltage and current; an inverter unit that includes a semiconductor bridge circuit for modulating the DC voltage based on a predetermined voltage value to generate a sinusoidal AC voltage, and a filter circuit inserted between the semiconductor bridge circuit and the load device in series; and a trip switch for connecting and tripping the inverter unit to and from the load device with respect to the failure determination of the control unit, wherein the control unit is further configured to generate a failure determination signal based on a deviation between an inductor current flowing through an inductor in the filter circuit and a simulated value as an estimated value of the inductor current generated by using a circuit constant of the inverter unit.