Abstract: A method and system for responding to a fast trip protective element trip in a generator system that re-excites the generator when a fast trip protection element trips and determines whether the generator immediately retrips the fast trip protection element, thereby determining whether a fault is located in the generator or in an attached load. If it is determined that the fault is located in the load, the system re-excites and reconnects the load after disabling the fast trip protection element for a specified period to allow for the load to clear its fault.

Abstract: A method of limiting a generator voltage in an overvoltage condition includes the steps of determining an amount of overvoltage of a generator output voltage exceeding a specified voltage and calculating a reference threshold voltage based upon the duration of overvoltage. A switch is modulated according to a voltage error between the output voltage and the reference threshold voltage. The current flow within the generator is interrupted based upon the voltage error to limit the output voltage to a desired voltage.

Abstract: A generator includes a permanent magnet generator, an exciter and a main generator mounted for rotation on a shaft. The main generator is configured to produce a voltage output. A generator control unit includes a circuit configured to provide current from the permanent magnet generator to the exciter. A switch is provided in the circuit and is configured to change between open and closed conditions. The switch is configured to flow current in the circuit in the closed condition and interrupt current flow in the open condition. An overvoltage limit controller is programmed to determine an amount of overvoltage of the output voltage exceeding a desired voltage.

Abstract: An example method of detecting a generator overvoltage condition includes predicting a primary control current to provide a predicted control current, monitoring the primary control current, and detecting a generator overvoltage condition based on a comparison of the predicted control current to the primary control current. The method interrupts the primary control current based on the comparing.

Abstract: A method and system for responding to a fast trip protective element trip in a generator system that re-excites the generator when a fast trip protection element trips and determines whether the generator immediately retrips the fast trip protection element, thereby determining whether a fault is located in the generator or in an attached load. If it is determined that the fault is located in the load, the system re-excites and reconnects the load after disabling the fast trip protection element for a specified period to allow for the load to clear its fault.

Abstract: An overvoltage protection system for a power generating system includes a generator control relay (GCR) controlling a conduction path through a generator exciter field, a flyback impedance in parallel communication with the generator exciter field, the flyback impedance configured to dissipate energy from the generator exciter field in response to opening of the conduction path, a gate drive configured to open and close the GCR, and an overvoltage prevention unit in signal communication with the gate drive, the overvoltage prevention unit configured to monitor a voltage and a current associated with the generator and selectively open and close the conduction path in response to the monitored voltage and current.

Abstract: An example method of detecting a generator overvoltage condition includes predicting a primary control current to provide a predicted control current, monitoring the primary control current, and detecting a generator overvoltage condition based on a comparison of the predicted control current to the primary control current. The method interrupts the primary control current based on the comparing.

Abstract: An electric power generation system has a synchronous machine, a starter excitation source and an exciter field driver. The starter excitation source is connected to the synchronous machine via multiple phase connections, and the exciter field driver is connected to the synchronous machine via a portion of the same phase connections. At least one of the phase connections is connected to each other phase connection via a transient voltage suppressor.

Abstract: A generator includes a permanent magnet generator, an exciter and a main generator mounted for rotation on a shaft. The main generator is configured to produce a voltage output. A generator control unit includes a circuit configured to provide current from the permanent magnet generator to the exciter. A switch is provided in the circuit and is configured to change between open and closed conditions. The switch is configured to flow current in the circuit in the closed condition and interrupt current flow in the open condition. An overvoltage limit controller is programmed to determine an amount of overvoltage of the output voltage exceeding a desired voltage.

Abstract: An aircraft electrical system comprises a generator to be driven as part of a gas turbine engine. The generator supplies electrical power to a plurality of accessories associated with the gas turbine engine, and to an aircraft power bus in parallel to the supply to the accessories. A control detects a short circuit on the aircraft power bus. When a short circuit is detected on the aircraft power bus, a switch is driven open to disconnect the aircraft power bus from the generator. In this manner, the power will continue to be delivered to the plurality of accessories. In a separate feature, a control voltage is provided by an auxiliary permanent magnet generator to a voltage regulator for the main generator.

Abstract: A method of detecting a parallel source condition includes calculating a reactive power, comparing the reactive power to a predetermined threshold, and determining a parallel source condition in response to the reactive power exceeding the predetermined threshold.

Abstract: A controller continually updates rotor time constant estimation of an induction machine by interrogating the induction machine with a small signal oscillation and monitoring the response. The small signal oscillation is injected onto the d-axis current command signal, and is generated at a frequency that represents the most recent estimate of the rotor time constant (i.e., rotor time constant equal the inverse of the frequency). The controller monitors rotor flux generated in response to the small signal oscillation, and updates the most recent estimate of the rotor time constant based on the monitored rotor flux. This process is repeated continuously to allow for the continuous updating of the rotor time constant.

Abstract: An electric generator with a rotating diode fault detection device built in that operates by comparing a voltage buildup across the exciter DC supply with a preset threshold value and determining if a fault condition is present based on the comparison.

Abstract: A method of detecting and monitoring torsional oscillation in a mechanical coupling between a prime mover and a multiphase alternating current (AC) electrical generator, comprises the steps of: detecting in at least one received signal variations that are indicative of changes in the rotational speed of the electrical generator; extracting information from the detected variations that are indicative of torsional oscillation to produce a torsional oscillation signal that has information relating to at least the amplitude of the torsional oscillation; and monitoring the torsional oscillation signal to determine the presence and severity of the torsional oscillation in the mechanical coupling.

Abstract: A negative sequence feedback circuit is connected to monitor and minimize unbalances in a high-frequency ac carrier signal provided to a motor/load for the purpose of detecting rotor position. The negative sequence feedback circuit detects unbalances in the high-frequency ac carrier signal and generates negative sequence feedback. The feedback is combined with command signals used to generate the high-frequency ac carrier signal, and the combination of the command signals with the negative sequence feedback is provided to an inverter for generation of the high-frequency ac carrier signal, wherein the negative sequence feedback reduces unbalances in the resulting high-frequency ac carrier signal such that a balanced high-frequency carrier signal is provided to the motor/load.

Abstract: A generator control unit (GCU) provides active damping of a synchronous generator by monitoring the speed of the synchronous generator and detecting oscillations in the monitored speed. The oscillations are indicative of torsional oscillations within the mechanical drivetrain including the synchronous generator or generators. In response to detected oscillations in the monitored speed, the GCU generates a varying set-point value that is used to control the excitation voltage provided to the synchronous generator. Varying the excitation voltage provided to the synchronous generator causes a variation in synchronous generator torque. By selectively varying the torque in the synchronous generator, the GCU provides active damping in the synchronous generator that decreases or dampens the torsional oscillations.

Abstract: An aircraft electrical system comprises a generator to be driven as part of a gas turbine engine. The generator supplies electrical power to a plurality of accessories associated with the gas turbine engine, and to an aircraft DC bus in parallel to the supply to the accessories. A battery supplies voltage to a control circuit for the generator through a selectively opened and closed switch. A control detects a short circuit on the aircraft DC bus. The battery switch allows power from the battery to flow to provide control voltage for the generator when the control detects a short circuit on the aircraft DC bus.

Abstract: A generator control unit (GCU) provides active damping of a synchronous generator by monitoring the speed of the synchronous generator and detecting oscillations in the monitored speed. The oscillations are indicative of torsional oscillations within the mechanical drivetrain including the synchronous generator or generators. In response to detected oscillations in the monitored speed, the GCU generates a varying set-point value that is used to control the excitation voltage provided to the synchronous generator. Varying the excitation voltage provided to the synchronous generator causes a variation in synchronous generator torque. By selectively varying the torque in the synchronous generator, the GCU provides active damping in the synchronous generator that decreases or dampens the torsional oscillations.

Abstract: A dual channel power generation system comprises: a prime mover; a permanent magnet (PM) dynamoelectric machine that has a PM rotor coupled to the prime mover, two multiphase alternating current (AC) stators that develop electromotive force (EMF) in response to rotation of the PM rotor due to the magnetic flux linkage between the PM rotor and the stators, two control coils that each change the magnetic flux linkage of a respective stator in response to the level of a control current that passes through the control coil; a multiphase AC rectifier for each stator that receives AC power from its respective stator to supply DC power on a respective rectifier bus; a current feedback loop for each rectifier bus; a voltage feedback loop for each rectifier bus; a load-sharing controller responsive to both current feedback loops to develop a voltage regulator reference signal for each rectifier bus that is representative of the value of voltage that its corresponding stator should produce to maintain equal values of c

Abstract: An electric power generation system has a synchronous machine, a starter excitation source and an exciter field driver. The starter excitation source is connected to the synchronous machine via multiple phase connections, and the exciter field driver is connected to the synchronous machine via a portion of the same phase connections. At least one of the phase connections is connected to each other phase connection via a transient voltage suppressor.