Uninterruptible power supply, control method and power supply system

Abstract

An uninterruptible power supply, a control method and a power supply system for normally starting the uninterruptible power supply and securing switch devices are provided. The uninterruptible power supply includes a first rectification circuit, a charge-discharge circuit, a bus capacitor, a first switch circuit and a second rectification circuit. The first rectification circuit is connected to the charge-discharge circuit, and is configured to rectify a voltage outputted by the alternating current power supply. The charge-discharge circuit is connected to the bus capacitor, and is configured to charge the bus capacitor after boosting the voltage outputted by the first rectification circuit, until the voltage across the bus capacitor reaches a first voltage. The first switch circuit is connected to the second rectification circuit, and is configured to connect the alternating current power supply to the second rectification circuit. The uninterruptible power supply boosts the voltage through the charge-discharge circuit to reduce the voltage difference between the alternating current power supply and the bus capacitor. Then, the first switch circuit is switched on to normally start the uninterruptible power supply and secure the first switch circuit.