UNINTERRUPTIBLE POWER SUPPLY

摘要

The present invention provides an uninterruptible power supply having a three-level charger/discharger. The uninterruptible power supply comprises: a DC positive-polarity line; a neutral line; a DC negative-polarity line; a first capacitor connected between the DC positive-polarity line and the neutral line; a second capacitor connected between the neutral line and the DC negative-polarity line; a three-level half-bridge PWM rectifier connected to the DC positive-polarity line, the neutral line and the DC negative-polarity line to convert AC power from an AC power source into DC power; a three-level charger/discharger connected the DC positive-polarity line, the neutral line and the DC negative-polarity line in parallel with the three-level half-bridge PWM rectifier to charge/discharge a battery; and a three-level half-bridge PWM inverter connected the DC positive-polarity line, the neutral line and the DC negative-polarity line in parallel with the three-level half-bridge PWM rectifier and the three-level charger/discharger to convert the DC power of the three-level half-bridge PWM rectifier or the three-level charger/discharger into AC power to supply the AC power to a load.