| 摘要 |
1477017 Controlling rectifiers SIEMENS AG 24 July 1974 [30 July 1973] 32779/74 Heading H2F [Also in Division G3] In a control arrangement for controlling the current in a static converter operable to pass both continuous and non-continuous current to a load, e.g. a D.C. motor, a load simulator, for simulating during a period when the current is non-continuous, the load conditions which would prevail if the current were continuous, comprises a multiplier 10 arranged to vary its multiplication factor in such a period and a delay 11 arranged to act only during current gaps in said period. Fig. 1 (not shown) relates to a conventional three-phase bridge of thyristors feeding current from A.C. supply to the armature of a separately excited D.C. motor. A tacho dynamo provides a speed signal to a speed controller, the output signal I* of which is compared with the current I on the A.C. side of the converter and fed to a current controller 5 having a delay circuit 11 switched in only during gaps in the current and feeding a multiplier 10 in the form of an amplifier whose gain is adjusted according to a function generator 17 so as to simulate the response of the circuit during continuous operation. The state of a bi-stable 27 is changed by the output of a limit stage 28 in response to the commencement of a current gap 14. The state of the bi-stable 27 is monitored by means of two monostable flip-flops 25, 26 each having a relaxation time somewhat longer than the period of the pulse frequency of the static converter and control a further limit device 52 which, in turn, controls two FETs 18, 23 arranged so as to connect capacitor 19 in the feedback path of amplifier 21 during non-continuous operation only and so delay the response. An AND gate 37 controls an integrator 29 arranged so as to feed a signal to a function generator 17 so as to vary the gain of amplifier 10 in dependence on whether the current is continuous or non-continuous. The function generator 10 may comprise a plurality of biased diodes arranged to control the input or feedback of an amplifier. It is suggested that the time constant of the delay 11 may be equal to three times the period of the current pulse frequency and the gain of amplifier 10 may be ten times that during continuous current flow. In Fig. 9 (not shown) the multiplier may take the form of an amplifier having its gain controlled by FET in the feedback path and connected ahead of stage 5 which is formed by an amplifier having RC feedback so as to provide proportional and delay characteristics. The delay 11 is connected after the control stage 5. |
