PURPOSE: To reduce the abrasion of a brake shoe by controlling regenerative braking and jointly using regenerative braking control and dynamic braking control continuously and reversibly in response to stringing voltage.

CONSTITUTION: When power travelling control, a thyristor 9 is at ON, and the slip frequency of induction motors 6 is controlled by means of a three-phase inverter section 4. When a brake command is emitted, the ignition control signals of the thyristor 9 are released, and regenerated at the contact wire side by the loop of the three-phase inverter section 4, a reactor 2, a diode 10 and a high-speed breaker 1. When the voltage of a capacitor 3 reaches set value at that time, a switching element 11 is ignited, and regenerative currents are shunted to a resistor 12. The switching element 11 is arc-extinguished at a point of time when the one sixth cycle period of the output frequency of the three-phase inverter 4 is completed. When the voltage of the capacitor 3 drops, control is shifted to regenerative braking control again.