| 摘要 |
1,255,529. High voltage D.C. power transmission. HITACHI Ltd., and ZAIDAN HOJIN DENRYOKU CHUO KENKYUSHO. 22 Aug., 1969 [4 Sept., 1968], No. 42043/69. Heading H2F. [Also in Divisions G2-G3] The current in a D.C. transmission line 9 connecting a rectifier and an inverter, Fig. 2 (not shown), is maintained at a desired value by a retroactive control loop comprising a current detector 11, filter 13, comparator 15 and amplifier 18 whose output controls a phase shifter 27 for determining the firing angle of the rectifier, this angle also being controlled by further control loops responsive to the output of the detector 11 to override the main control loop during sudden changes of the current. The further control loops comprise comparators 16, 17, amplifiers 19, 20 and diodes 24, 25, the parameters of these loops being chosen so that for sudden increases of current the loop 16, 19 takes over control of the phase shifter 27 and for sudden decreases the loop 17, 20 takes control. A discussion is given of the operation under conditions of slow or sudden current change, having regard to such parameters as the time constant of the filter 13, the amplifier characteristics, the polarity and breakdown voltage of the diodes 23, 24, 25 and the choice of the setpoints of the further loops in relation to the setpoint Id for the main loop.
|
