The illustrated embodiments include an exciting generator and a power generator. Each of the generators includes a common tubular rotor. The armature of the exciting generator is maintained within the rotor and is fed through a control rectifier to the field of the power generator, which is also maintained within the rotor. The output voltage of the power generator is sampled for modulation of a radio transmitter which delivers power to a transmitting antenna. A receiving means maintained within the tubular rotor receives and demodulates the signal from the transmitter. The demodulated signal, together with the output of the field generator armature is applied to the control elements of the control rectifier and thus determines the intensity of the power generator field and, correspondingly, the output of the power generator.
This is a continuation-in-part application of our copending application Ser. No. 724,478; filed Apr. 26, 1968; titled ELECTRIC GENERATOR CONTROL SYSTEM.
Thyristors are substituted for conventional diodes in the rotating rectifier assembly of a brushless exciter in a synchronous dynamoelectric machine. In contrast with prior systems in which thyristors are switched at relatively high ceiling voltages (requiring thyristors of high power rating and additional components for fast de-excitation), the gates of the thyristors in the present invention are fired only at a low voltage point of the negative half cycle of the polyphase armature voltage waveforms for fast de-excitation and are maintained in a fully conducting condition during the positive half cycle. This permits the use of thyristors having a relatively lower power rating and makes unnecessary additional components to achieve fast de-excitation.
A shaft torsional oscillation signal of a rotatable torsional system including a rotor of a synchronous machine, at least one rotatable body and a shaft coupling the synchronous machine and the rotatable body, is detected. The shaft torsional oscillation signal with a specific frequency is made to advance the phase thereof by a stabilizing control device. The field voltage of the synchronous machine is so controlled that a sub-synchronous resonance (SSR) of the rotatable torsional system caused by the specific frequency is restrictedly controlled by the shaft torsional signal of the specific frequency phase-advanced.
