Traction system circuit and power supply mode switching method thereof

The invention discloses a traction system circuit and a power supply mode switching method thereof, and the circuit comprises a high-voltage box which comprises a KMM contactor; one end of the traction converter module is connected with the KMM contactor, the traction converter module comprises a DC/DC chopping module and an inverter module, and the DC/DC chopping module is integrated to the inverter module; the TCU traction controller is respectively connected with the traction converter module and the high-voltage box, and the TCU traction controller detects data of the high-voltage box and data of the traction converter module and adjusts the state of the KMM contactor according to the data of the high-voltage box and the data of the traction converter module; the vehicle-mounted energy storage module is connected with the DC/DC chopping module; and after the TCU traction controller judges whether the traction converter module data and the high-voltage box data cross a zero point or not according to a doub