Traction power converter for multisystem rail vehicle

In a rail vehicle passing along catenary voltage sections including an AC and a plurality of DCs, an arrangement is provided to solve a problem that the output of the vehicle is reduced under the lower voltage of the DC voltages and to achieve a reduction in voltage for an auxiliary power supply. The present invention includes a current collector capable of collecting two DCs under different voltages, an inverter configured to control an AC motor, an inverter configured to perform constant voltage constant frequency control under a voltage lower than that of the inverter configured to control the AC motor, a step-up/down chopper capable of stepping-up/down voltage; and circuit switching means capable of switching a current path selectively. Under a higher voltage, power stepped-down by the step-up/down chopper is supplied to the inverter configured to perform the constant voltage constant frequency control. Under a lower voltage, power stepped-up by the step-up/down chopper is supplied to the inverter configured to drive the AC motor.