Power supply unit during loopback that friendship - direct current locomotive is fireless

The utility model provides a friendship power supply unit during the loopback that the direct current locomotive is fireless, including power management module, excitation copped wave module, rectification voltage -stabilizing module, interchange contravariant module and original locomotive storage battery, the output and traction motor excitation coil's the both ends of excitation copped wave module are connected, and rectification voltage -stabilizing module's input is connected with traction motor's armature both ends, and the output that exchanges the contravariant module is connected withthe locomotive cab load, before the traction motor of locomotive got into generating state, the input of excitation copped wave module all was connected with locomotive storage battery's output withthe input that exchanges the contravariant module, after the traction motor of locomotive gets into generating state, the input of excitation copped wave module and the input that exchanges the contravariant module all with lo