Abstract: An uninterruptible power supply. A rectifier of the uninterruptible power supply includes six first rectifier diodes, six second rectifier diodes, three alternating current side relays, six direct current side relays, a DC/DC conversion unit, and a controller. The other end of each alternating current side relay is connected to anodes of two first rectifier diodes, and cathodes of the two first rectifier diodes are respectively connected to two phases of positive input ends of the DC/DC conversion unit. The other end of each alternating current side relay is further connected to cathodes of two second rectifier diodes, and anodes of the two second rectifier diodes are respectively connected to two phases of negative input ends of the DC/DC conversion unit.

Abstract: The present application provides a three-level inverter and power supply equipment, including: a first IGBT, where a collector thereof is connected to a positive direct current bus, an emitter thereof is connected to a first connection point, and the collector and the emitter are bridge-connected to a first freewheeling diode; a second IGBT, where a collector thereof is connected to the first connection point, an emitter thereof is connected to a second connection point, and the collector and the emitter are bridge-connected to a second freewheeling diode; a third IGBT, where a collector thereof is connected to the second connection point, an emitter thereof is connected to a third connection point, and the collector and the emitter are bridge-connected to a third freewheeling diode; a fourth IGBT, where a collector thereof is connected to the third connection point, an emitter thereof is connected to a negative direct current bus.