Abstract:
A thyristor rectifier for high voltage includes a number of series-connected thyristors with a control device for each thyristor and a control circuit for the whole rectifier connected to the control devices. There is a control pulse emitter in each control device which emits an indicating pulse when the voltage over the corresponding thyristor in the conducting direction amounts to a certain value. A protection device is provided which emits a signal for the whole rectifier through a control pulse transmitter if a voltage grows in the conducting direction of the rectifier at a time when only an insufficient number of thyristors have regained their blocking ability. This protection device includes a memory circuit and a counter to register the indicating pulses from the emitters of the control devices and an output circuit connected between the counter and the control pulse transmitter which emits a signal for ignition of the whole thyristor in dependence on a predetermined number of indicating pulses.
Abstract:
An arrangement for phase angle control of converters which is intended to deliver to a control device for the converter rectifier a signal to set the phase angle of the control pulses includes a control circuit to the input side of which is delivered the difference between the real value and a desired value of the converter current. When the control circuit is stationary, the difference between the current values as well as the signal delivered to the control device is zero. The circuit includes a compensator connected between the input side and the output side of the control circuit, the input side of the compensator being connected to the control circuit over a connecting member which is briefly connected in by the control pulses to the converter rectifiers. The output side of the compensator is connected to the output side of the control circuit in such a way that the output signal of the compensator is subtracted from the original output signal of the control circuit.
Abstract:
An electronic power convertor which has a plurality of rectifiers arranged in a bridge connection is provided with a pulse generator and with connecting members in the circuit between the pulse generator and the rectifiers. Connecting members in the connection between the pulse generator and the rectifiers are controlled by control circuits which, in response to a blocking signal, render the connecting members inoperative, so that control voltage is no longer supplied to the rectifier from the pulse generator directly through the connecting members. However, the control circuit also acts to continue the supply of control voltage to one of the rectifiers which are conducting at the time that the blocking signal is initiated and to the corresponding rectifier of the same phase of the bridge, so that these two rectifiers will conduct and form a by-pass circuit. In case of deblocking of the rectifier, each commutation group of the bridge is deblocked separately by the normal control pulse for the proper rectifier of the group acting in the by-pass circuit.