System structure using common-mode voltage as auxiliary power supply

The utility model discloses a system structure using common-mode voltage as an auxiliary power supply, which comprises a PWM inverter and a motor driven by the PWM inverter, and further comprises a Y-connection capacitor, a transformer, a rectifier and an LC filter which are connected in parallel on a three-phase cable between the PWM inverter and the motor, the Y-connected capacitor is used for extracting common-mode voltage on the transmission line; common-mode voltage passes through the Y-connection capacitor, the transformer, the rectifier and the LC filter and then outputs a DC power supply. Compared with a processing method for suppressing common-mode voltage in a traditional motor driving system, the system can well utilize the energy of the common-mode voltage; compared with the traditional method for extracting the common-mode voltage from the neutral point of the load motor, the method considers the problem that the neutral point cannot be led out from part of motors, so that the method for obtainin