Method and device for recovering mixed regenerative energy of urban railway power supply system

The invention discloses a method and a device for recovering mixed regenerative energy of an urban railway power supply system. The method comprises the steps of determining an energy feedback/absorption mode according to the AC power grid failure state, controlling an energy feedback converter to feed regenerative brake energy back to the AC power grid in the energy feedback mode, and converting regenerative brake energy into direct-current low-voltage electricity to be absorbed by an energy absorption component in the energy absorption mode. The device comprises a direct-current disconnecting switch unit, an energy feedback transformer, a converter control unit and at least one converter unit. Each of the at least one converter unit comprises the energy feedback converter, an energy feedback branch switch K1, an energy absorption branch switch K2 and three energy absorption components. By means of the method and the device, regenerative brake energy is absorbed by the energy absorption component during the failure of the AC power grid to maintain the stability of the DC power grid voltage, and the connection between the energy recovery device and the DC power grid is not needed to be cut off, so that the safe reliability of the energy recovery device is improved, the structure of a chopper can be omitted, and costs are saved.