| 摘要 |
PROBLEM TO BE SOLVED: To suppress an output voltage waveform distortion caused by a bus voltage drop and to improve input/output efficiency during high current charging in the case where an output current is high in an uninterruptible power supply of a constant inverter system.SOLUTION: The uninterruptible power supply includes: a converter section 27 for converting power of an AC power source 1 to DC power; an inverter section 24 for converting the DC power into AC power; a balancing section 25 for performing voltage balancing on a capacitor 24a and a capacitor 24b; and a negative electrode side step-up/down section 26 which drops a voltage of power of the capacitor 24b and a power storage section 23 is charged with the power. In the case where a detection value of an output current sensor 6 exceeds a fixed value, in accordance with an excessive current value, the negative electrode side step-up/down section 26 suppresses a current with which the power storage section 23 is charged, and suppresses power to be extracted from the capacitor 24a and the capacitor 24b. Thus, the bus voltage reduction is suppressed and the distortion of an output voltage generated by the inverter section 24 can be eliminated. |
