Abstract: A power distribution circuit of an uninterruptible power supply is provided, where a first port of the power distribution circuit of the uninterruptible power supply is electrically connected to a second port. A third port is electrically connected to the second port by using a compensation circuit. When an input voltage of the first port is less than a rated voltage of a load of the second port, an input voltage of the third port is input to the compensation circuit. The compensation circuit converts a direct current into an alternating current, so that the alternating current output by the compensation circuit and the input voltage of the first port jointly supply power to the load of the second port.

Abstract: A modular multilevel converter (MMC) includes an input conversion module, an output conversion module, a common conversion module, and a common bridge arm. One end of the input conversion module is connected to Vin, the other end of the input conversion module is connected to the common conversion module through the common bridge arm, and the common conversion module is connected to Vin and Vout. One end of the output conversion module is connected to the common conversion module through the common bridge arm, and the other end of the output conversion module is connected to Vout. The input conversion module and the output conversion module share one bus capacitor.