Abstract: A variable-speed power generating system comprises a variable-speed generator electrically connected at its primary winding to an electric power system and its secondary winding to the electric power system through a frequency converter and mechanically coupled to a driver driving the secondary side thereof, a phase detector generating an output signal representing a slip frequency in response to the application of a first input having a frequency component of an output generated from the primary winding of the variable-speed generator and a second input having a frequency component corresponding to the rotation speed of the driver, a controller controlling the frequency converter on the basis of a reference phase provided by the output signal of the phase detector, and regulating means for controlling the frequency converter so that, when the variable-speed generator is disconnected from the electric power system, the frequency applied to the secondary winding of the variable-speed generator may not deviate

Abstract: A control system for a variable speed water turbine generator apparatus includes a first function generator that is responsive to an output command signal. The first function generator produces a rotation number command signal. A speed adjuster produces an output signal in accordance with a different signal between the first function generator output and an actual rotation number. An adder adds the generator output command signal to the speed adjuster output signal to determine an overall output command signal. An output aduster produces an output signal in accordance with a difference between the adder output and an actual power output of the generator for controlling the firing angles of the frequency converter. A second function generator, responsive to the generator output command signal, determines an opening command signal for the variable opening vanes.

Abstract: There is disclosed a protecting apparatus for a secondary excitation type variable speed AC generator/motor having a primary winding connected to an electric power system and a secondary winding each phase of which is AC excited by an independent power converter unit. The protecting apparatus is arranged to detect an electrical event which includes at least one of an overvoltage and overcurrent appearing at each phase of the secondary winding of the AC generator/motor, to decide whether the detected electrical event meets a predetermined condition and to close, when the electrical event detected in respect to any of phases of the secondary winding is decided as meeting the predetermined condition, a switch circuit connected in the corresponding phase of the secondary winding.

Abstract: An induction generator/motor system has an induction machine connected at its secondary side to a cyclo-converter. An induced voltage develops when the cyclo-converter pauses during a transient phenomenon occurring in the system. When the induced voltage exceeds a predetermined voltage range which covers the maximum output voltage derivable from the cyclo-converter, the polarity of thyristor converters of the cyclo-converter is switched such that the induced voltage is applied to a thyristor converter to be rendered conductive next in forward relationship therewith, thereby preventing occurrence of an overvoltage.

Abstract: Disclosed is a control apparatus for a variable-speed hydraulic power generating system comprising a variable-speed a.c. electric generator connected to an a.c. electric power system and a hydraulic machine system including a water turbine for driving the generator and a guide vane for controlling an amount of water supplied to the water turbine.

Abstract: In a pumping-up generator/motor system comprising an induction generator/motor, at least one cyclo-converter connected to the secondary winding of the induction generator motor for controlling the rotational speed of the generator/motor in the motor mode and for maintaining the output frequency thereof in the generator mode at a constant level, the center of the speed range of the generator/motor in the generator mode is set near the synchronous speed thereof and a plurality of converter units constituting each cyclo-converter are connected in parallel in the generator mode, and in series in the motor mode thereby allowing the capacity of the cyclo-converter to be made smaller.

Abstract: A control system for variable speed hydraulic turbine generator apparatus comprises an induction generator connected at its primary side to an AC power line system, a secondary excitation controller connected to the secondary side of the induction generator and being responsive to a generator output command signal supplied externally to supply to the induction generator an excitation current which causes the induction generator to generate AC power at the same frequency as that on the AC power line system, a hydraulic turbine for rotating the induction generator, a guide valve for regulating the amount of water supplied to the hydraulic turbine, a rotation speed detector for detecting a rotation speed of the induction generator, a rotation speed command calculator for receiving a hydraulic turbine running condition signal inclusive of the external generator output command signal and calculating an optimum rotation speed command, a rotation speed controller for comparing the optimum rotation speed command with