| 摘要 |
PURPOSE:To eliminate an insulating transformer even when neutral grounding is required, and to realize an output power supply constitution equivalent to input power supply constitution regardless of the phase difference of each phase voltage with respect to the supply side neutral point. CONSTITUTION:The uninterruptible power supply comprises converters 1a, 1b for converting an AC voltage of an AC power supply having neutral point, e.g. single-phase three-ware or three-phase four-wire system, into a positive or negative DC voltage with respect to the neutral point, a battery subjected to floating charge with DC output voltage from the converter, and a thyristor switch 5 operable upon interruption of AC power supply to produce DC power from the battery 4. The uninterruptible power supply further comprises inverters 6a, 6b for converting DC power from the converters 1a, 1b or the battery 4 into AC power equivalent to the power of AC power supply with respect to the neutral point, and a switch 7 switching between the output from the inverter and an input power direct feed circuit. |
