DC ELECTROMOTIVE SYSTEM FOR ELECTRIC RAILROAD

摘要

PROBLEM TO BE SOLVED: To solve the problem in an energy storage device that simply storing regenerative power from an electric railroad into a battery and regenerating it results in poor efficiency of utilizing the device and poor efficiency of facilities. SOLUTION: A step-up/step-down chopper 12 lowers that portion of the voltage of a dc power storage device 11 which does not contribute to charge to and discharge from a feeder, to thereby achieve a high step-up/step-down ratio for achieving desired charge and discharge voltages, for the purposes of controlling a charge current from the feeder to the dc power storage device 11 when the feeder voltage is equal to or greater than a charge-controlling set voltage and of controlling a discharge current from the storage device to the feeder when the feeder voltage is equal to or less than a discharge-controlling set voltage. A stopper switch 13 blocks a natural discharge from the storage device to the feeder side through the chopper. A filter capacitor 14 and a reactor 15 suppress higher harmonies flowing from the chopper to the feeder side. A current detector 20 performs current detection for controlling the charge and discharge currents of the chopper.