Cutoff method of uninterruptible power supply and uninterruptible power supply

摘要

Performance failure in an uninterruptible POWER supply (UPS) is determined independently by itself. A selective tripping can be done within a shorter time than one cycle of an AC output. A UPS converts a DC voltage to an AC voltage and supplies the AC voltage to a load device. A UPS has a control unit conducting a failure determination by using an instantaneous value of an internal voltage and current. It is preferred that a UPS includes an inverter unit and a trip switch. The inverter unit includes a semiconductor bridge circuit generating a sinusoidal AC voltage by modulating a DC voltage with voltage instruction values and a filter circuit inserted between the semiconductor bridge circuit and the load device. The trip switch connects and trips a connection between the inverter unit and the load device according to the failure determination of the control unit.