| 摘要 |
PROBLEM TO BE SOLVED: To provide a control device by which voltage unbalance in a DC part of an uninterruptible power supply is suppressed and operation can be continued without exerting adverse influences upon power supply to a load.SOLUTION: The control device for controlling an uninterruptible power supply 10 including a three-level converter 11, a three-level inverter 12 and a bypass circuit 15 for supplying an AC voltage to a load in place of inverter power supply includes: unbalance monitoring means 20 and caution generation means 30 for generating a caution indicating DC voltage unbalance when a deviation between a voltage Eof a capacitor Cdefining a potential at a DC neutral point Nof a DC part 14 as a reference and a voltage Eof a capacitor Cexceeds a first reference value; and gain adjustment means 51 for switching a control gain of the converter 11 to a gain for DC voltage unbalance suppression when the deviation exceeds the first reference value.SELECTED DRAWING: Figure 1 |
