Multi-current-type current-changing system

The invention provides a multi-current-type current-changing system. A direct current or an alternating current supplied by a power supply is received by the system; judgment can be conducted by a transmission controller according to a received power supply mode; when the power supply is an alternating current power supply, a rectifier is connected to the system, so that the received alternating current is rectified by the rectifier, an obtained direct current is sent to a middle direct-current circuit to be processed, and when the power supply is a direct current power supply, the direct current is directly sent to the middle direct current circuit to be processed; after the direct current processed through the middle direct current circuit continuous to be inverted into the alternating current, the alternating current is output to a tractor motor of a locomotive through a first output device so that rated traction or traction of the locomotive is achieved. By the adoption of the multi-current-type current-changing system, voltages supplied by the power supplies of different types can be received and processed, electricity is supplied to the locomotive, when the power supply mode of the locomotive is changed, it is not required that transported cargoes are transferred to other locomotives matched with the changed power supply mode, the period for cargo transportation is shortened, and the transportation cost is reduced.