GE Energy Power Conversion Technology Patente

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The disclosure relates to a pod propulsion system (300) including first and second counter rotating propellers (318, 322) for providing thrust to propel a marine vessel. The pod propulsion system (300) includes a first electric motor (314) for rotating the first propeller (318) and electrically coupled to a first drive (304) that is configured to control the first electric motor (314). The pod propulsion system (300) also includes a second electric motor (316) for rotating the second propeller (322) and electrically coupled to a second drive (306) that is configured to control the second electric motor (316). The first and second drives (304, 306) respectively control the first and second electric motors (314, 316) interdependently.

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A method of controlling a power system is described. The power system includes an electrical machine, e.g., wind turbine generator, a power converter and a DC circuit. A dynamic braking system (or DBS) includes a braking circuit connected in series to the DC circuit. The braking circuit includes a braking resistor and a chopper. The method comprising the steps of: operating the DBS and controlling operation of the electrical machine based on a prevailing temperature of the braking circuit. The method can further comprise the step of stopping the electrical machine. The electrical machine can be controlled to be restarted at its rated output power once the prevailing temperature of the braking resistor reaches or falls below a lower temperature threshold. Alternatively, the electrical machine can be restarted at a lower output power and, after restarting, its output power can be increased based on a power starting profile as the braking resistor cools.

A power converter system (1A) is described. The system includes a power converter (2) with a first converter (2b) including a plurality of semiconductor devices. Each semiconductor device includes at least a controllable semiconductor switch having a threshold voltage and a gate voltage for normal on-state conduction. The first converter (2b) has first and second DC terminals connected to a DC circuit (22), and a plurality of AC terminals. A controller is configured to supply current to the first converter (2b) (e.g., from an AC power source (24)) and enable a short circuit state of the first converter by controlling semiconductor switches of the first converter to create at least one short circuit path through the first converter that carries the supplied current. At least one of the semiconductor switches in at least one of the short circuit paths is operated with modified on-state conduction in order to increase conduction losses. A gate driver applies to the semiconductor switch a modified gate voltage that is less than the gate voltage for normal on-state conduction.

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A power distribution system (1") is described. The power distribution system (1") comprises a plurality of power converter systems (2<1>-2<4>) electrically connected to a distribution bus (5) which defines a point of common coupling. Each power converter system (2<1>-2<4>) includes a power converter (3<1>-3<4>) with a plurality of semiconductor switching devices controlled using a PWM strategy with a switching frequency. A controller (12<1>-12<4>) for each power converter system (2<1>-2<4>) is provided. Each controller (12<1>-12<4>) is adapted to apply a spectrum analysis process to the respective power converter system that uses measured or derived zero sequence currents associated with the respective power converter system to determine the location of a ground fault within the power distribution system. Each controller (12<1>-12<4>) is adapted to apply a switching frequency process where the switching frequency of the power converter of at least one of the power converter systems is different from the switching frequency of the power converter of at least another one of the power converter systems during at least part of the time that the spectrum analysis process is applied.

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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".

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A stator for an electrical machine is described. The stator includes a plurality of axially adjacent generally annular laminations (10). An axially extending coolant passageway (40) through which a coolant fluid flows in use, extends through the stator. A plurality of axially spaced sealing recesses (44) are provided. Each sealing recess (44) is located between a pair of laminations (10) and is in open communication with the surface (42) of the axially extending coolant passageway (40). Each sealing recess (44) has an axial width greater than the gap between the facing planar surfaces of axially adjacent laminations (10) and is at least partially filled with a cured resin material to define a plurality of axially spaced seals (50).

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Es ist ein Verfahren zum Betreiben eines Kraftwerks (1) mit einer doppelt gespeisten Asynchronmaschine (11) und einem Umrichter (17) in einem Betriebsmodus der virtuellen Massenträgheit zur Stützung der Netzfrequenz offenbart. Das Verfahren weist auf, dass, wenn eine aktuelle mechanische Drehzahl (n<r>) des Rotors (13) in einem vorbestimmten Drehzahlbereich ([n<VM->; n<VM+>]) um eine Synchrondrehzahl (n<syn>) des Rotors (13) herum oder eine aktuelle Rotorfrequenz (f<r>) in einem vorbestimmten Frequenzbereich ([f<VM->; f<VM+>]) um eine Nullfrequenz des Rotors (13) herum liegt, ein aktueller maximalen Stromgrenzwertes (I<r,max>) für einen durch den Umrichter (17) bereitzustellenden Rotorstrom in Abhängigkeit von den aktuellen Werten der Drehzahl (n<r>) bzw. Rotorfrequenz (f<r>) und der Drehzahländerungsrate (dn<r>/dt) bzw. Frequenzänderungsrate (df<r>/dt) des Rotors (13) reduziert wird. Das Verfahren weist ferner auf, dass ein aktueller Sollwert (I<r>) für den Rotorstrom basierend auf einer Leistungsanforderung (P*, Q*) vom Netz (2) in Abhängigkeit von gemessenen aktuellen Betriebsgrößen bestimmt wird. Das Verfahren weist ferner auf, dass der Umrichter (17) angesteuert wird, um pulsartig sinusförmige Spannungen und Ströme mit dem aktuellen Rotorstromsollwert (I<r>), begrenzt auf den aktuellen maximalen Rotorstromgrenzwert (I<r,max>) an den Rotor (13) zu schalten. Eine Umrichtervorrichtung (26) und ein Kraftwerk (1) mit dieser sind ebenfalls offenbart.

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