Systems and methods for operating an uninterruptible power supply

摘要

An uninterruptible power supply includes a first input (202) to receive input power from an input power source, an output (230) to provide output power, a switch (206), a first logic power supply (210) coupled to the switch, a back-up power source (216), a charger (220), a main logic power supply (212) and power converter circuitry. The switch (206) is configured to close when a characteristic of the input power is within a selected range. The first logic power supply is coupled to the switch and configured to receive input power from the input power source when the switch is closed. The first logic power supply has a first DC output. The back-up power source has a second DC output and is coupled to the first DC output at a common node. The charger (220) has a third DC output and is coupled to the common node. The main logic power supply (212) is coupled to the common node and is configured to receive at least one of the first DC output, the second DC output and the third DC output. The power converter circuitry is coupled to the backup power source and the first input and is configured to provides the output power derived from at least one of power at the first input and power from the backup power source.