The present subject matter is directed to a system and method for operating an electrical power circuit connected to a power grid. The power circuit includes a power converter electrically coupled to a generator. The method includes monitoring at least one speed condition of the generator during operation of the power circuit. Another step includes determining one or more voltage conditions of the power circuit. The method also includes calculating a maximum reactive current for the generator as a function of at least one of the speed condition or the one or more voltage conditions. Thus, the method also includes operating the generator based on the maximum reactive current so as to prevent an actual modulation index of the power converter from exceeding a predetermined threshold.

The present subject matter is directed to a method for controlling a generator of an electrical power system. The generator includes a generator stator magnetically coupled to a generator rotor. The method includes operating the generator stator of the generator at a first voltage level. Another step includes monitoring, via one or more sensors, at least one of a rotor speed or a rotor voltage of the generator rotor. The method also includes reducing the first voltage level of the generator stator by a predetermined percentage when the rotor speed is within a low speed range or the rotor voltage exceeds a predetermined threshold so as to increase an operating range of the rotor speed. Thus, the increased operating range of the rotor speed increases power production of the electrical power system in the low speed range.

An uninterruptable power supply (UPS) system for providing power to a load coupled to a utility power source is provided. The UPS system includes a doubly-fed induction generator (DFIG), a rechargeable energy storage system, a first inverter, and a controller in communication with the DFIG and the first inverter. The DFIG includes a stator and a rotor coupled to the load. The stator and rotor are magnetically coupled together. The DFIG generates an auxiliary power output. The first inverter is coupled between the rotor and the rechargeable energy storage system. The controller detects a power disturbance associated with the utility power source and controls the first inverter to provide an excitation input to the rotor in response to the power disturbance. The DFIG provides the auxiliary power output to the load based on the excitation input.

A generator system configured to be connected in parallel with other generators is disclosed. The generator system includes an alternator having a stator with an output winding and a quadrature winding and a rotor with a three-phase winding. The rotor of the alternator is rotatably driven by an engine having a controller to regulate the engine speed. An inverter receives power from the quadrature winding and generates an AC voltage for the rotor winding. The inverter receives an input corresponding to the voltage on the output winding of the stator and also receives an input corresponding to the phase angle of a second AC voltage produced by another power source. The inverter controls the frequency of the AC voltage for the rotor winding such that the phase angle of the voltage on the output winding of the stator is synchronized to the phase angle of the second AC voltage.

The present subject matter is directed to a system and method for operating an electrical power circuit connected to a power grid. The electrical power circuit has a power converter electrically coupled to a generator. The method includes monitoring a rotor speed of the generator during operation of the electrical power circuit. The method also includes increasing an operating range of the rotor speed of the generator. Further, the method includes determining at least one of a line-side voltage of a line-side converter of the power converter or a rotor-side voltage of a rotor-side converter of the power converter during operation of the electrical power circuit. Another step include controlling, via a converter controller, a DC link voltage of a DC link of the power converter as a function of one or more of the line-side voltage, the rotor-side voltage, and/or the rotor speed.

Control of alternator/starters for providing electrical power to a vehicle and rotating an engine is disclosed. In one example, the alternator/starter provides a differential action whereby torque on an input side of the alternator may be maintained while speed of an output side of the alternator may be varied. The alternator/starter includes two armature windings and two field windings.

A doubly-fed induction generator (DFIG) system (100) is described. The DFIG system (100) includes an induction electric machine (102) including a stator having a stator winding and a rotor having a rotor winding. The stator winding is electrically connected to at least one output terminal (108) and the rotor winding is electrically connected to the at least one output terminal (108) by means of a power converter. The power converter includes a first active rectifier/inverter (130a) with alternating current AC terminals electrically connected to the rotor winding, and direct current DC terminals, and a second active rectifier/inverter (136a) with DC terminals electrically connected to the DC terminals of the first active rectifier/inverter by a DC link (138a), and AC terminals electrically connected to the at least one output terminal (108). A controller is adapted to control the first active rectifier/inverter (130a) so that the frequency of the AC current at its AC terminals is substantially constant during at least one of a “line charging mode” and an “islanded mode”.

A secondary magnetic excitation generator-motor device that inputs a first ignition pulse command to a three-level NPC power converter such that a detected excitation current value corresponds with an excitation current command value, the secondary magnetic excitation generator-motor device having a function of identifying a first phase, a second phase, or a third phase in descending order of a current absolute value, wherein a pulse switch to output an ignition pulse command to the three-level NPC power converter switches the ignition pulse command to the second ignition pulse command when a current absolute value exceeds a set overcurrent level 1, and switches the ignition pulse command to the first ignition pulse command when current absolute values for three phases are all equal to or smaller than a set overcurrent level 2.

A method for operating a inverter-based resource connected to a power grid includes receiving one or more voltage feedback signals created by at least one component of the inverter-based resource, wherein distortion components of the one or more voltage feedback signals are more sensitive to voltage distortion created by the inverter-based resource than by external sources of voltage distortion. Further, the method includes extracting a distortion component of the one or more feedback signals having a certain phase sequence and frequency. Moreover, the method includes determining a voltage command for the power converter as a function of, at least, the distortion component. Thus, the method includes controlling the power converter based on the voltage command such that the voltage distortion created by the at least one component of the inverter-based resource is reduced in a manner that is relatively insensitive to voltage distortion created by sources external to the inverter-based resource.

A power generation equipment monitoring system includes a receiver and a determining processor. The receiver acquires, from a measuring device that measures output currents of power generation equipment that converts rotational energy of a rotor thereof into electric energy to output AC voltage with a reference frequency, waveform data representing waveform of the output currents. The determining processor determines presence and absence of a malfunction in a rotary block that applies motive power to the rotor of the power generation equipment, according to the waveform data acquired through the receiver. The determining processor determines the presence and absence of the malfunction based on a component of at least one specific frequency arranged at one or more intervals according to a rotational speed of the rotor from the reference frequency on a frequency axis in a frequency spectrum of the output currents.