| 摘要 |
PURPOSE:To reduce a loss in power by subjecting an inverter to phase control so as to run a set amount of circulating current during power running so as to aim at regenerating power with no delay, and by enabling the circulating current to be held at a constant value irrespective of variations in a.c. input voltage of a converter. CONSTITUTION:Current transformers CT1, CT2 for detecting current are disposed in a.c. current paths between a transformer 2a and a converter 3 and between a transformer 2b and an inverter 8, respectively. A/V converters 11, 22 convert detected currents into voltages which are compared with set values by comparing circuits 12, 23. An amplifier 14 amplifies a deviation from the circuit 12 and then delivers the same to a comparing circuit 16 so as to obtain deviations with respect to an electric overhead line voltage detection signals which are obtained by dividing the voltages of an inverter voltage setting unit 17 and of an electric overhead line 12 with the use of resistors R1, R2. Further, the gate of the inverter 8 is controlled by means of a phase shifter 19 and the like in accordance with the deviations. At this time when the deviation from the comparing circuit 23 is negative, the output of a deviation amplifier 18 is limited by means of a limiter circuit 26.
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