Abstract: 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.

Abstract: The present subject matter is directed to an electrical power circuit connected to a power grid and method of operating same. The electrical power circuit has a power converter electrically coupled to a generator, such as a doubly-fed induction generator, having a rotor and a stator. Thus, the method includes operating rotor connections of the rotor of the generator in a wye configuration during a first rotor speed operating range. Further, the method includes monitoring a rotor speed of the rotor of the generator. Thus, the method also includes transitioning the rotor connections of the rotor from the wye configuration to a delta configuration if the rotor speed changes to a second rotor speed operating range.

Abstract: A method for controlling a wind turbine system may generally include controlling a wind turbine to operate at a speed and torque setting within a permissible operating region defined between maximum and minimum operating curves, receiving a speed de-rate request and/or a torque de-rate request to de-rate the wind turbine based on a limiting constraint of the wind turbine system, determining an adjusted speed setting and/or an adjusted torque setting for the wind turbine based on the speed de-rate request and/or the torque de-rate request, determining whether an adjustment of the wind turbine operation to the adjusted speed setting and/or the adjusted torque setting would place the turbine outside the permissible operating region and, if the adjustment would place the operation outside the permissible operating region, adjusting the speed setting and/or the torque setting to a new speed and/or torque setting defined along the maximum or minimum operating curve.

Abstract: System and methods for optimizing operation of a wind turbine are disclosed. In one aspect, the method also includes determining, via a converter controller of a power converter, a tap position of a tap changer configured between the power grid and a primary winding of a transformer. Another step includes calculating, via the converter controller, a primary voltage of the primary winding as a function of the tap position. The method also includes implementing, via the converter controller, a control action if the primary voltage or a measured secondary voltage of a secondary winding of the transformer is outside of a predetermined voltage range.

Abstract: 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.

Abstract: 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.

Abstract: The present subject matter is directed to a method for initializing a startup sequence of a wind turbine. The method includes a step of defining a plurality of operating conditions of the wind turbine. As such, upon satisfaction of the plurality of operating conditions, a run-ready signal may be generated, wherein the run-ready signal indicates a readiness of a power converter of the wind turbine to generate power. The method may also include defining a subset of the plurality of operating conditions, wherein the subset of operating conditions are independent of speed conditions of the wind turbine. Another step of the method includes generating a spin-ready signal for the wind turbine upon satisfaction of the subset of operating conditions. The method may also include controlling a rotor of the wind turbine based at least in part on the spin-ready signal.

Abstract: A method and apparatus for testing operability of a power converter with an existing power conversion assembly of a renewable energy system is disclosed. The method includes transferring a first pulse of energy from an existing power conversion assembly to a power filter of the power converter through first cells within a bridge circuit of the power converter. Another step includes determining a first current-voltage feedback associated with the first pulse. A next step includes transferring a second pulse of energy from the power filter to the existing power conversion assembly through second cells within the bridge circuit such that a portion of the first pulse moves back to the existing power conversion assembly. Another step includes determining a second current-voltage feedback associated with the second pulse. The first and second current-voltage feedbacks are compared with nominal tolerances of the power converter to ensure the power converter is operating properly.

Abstract: The present subject matter is directed to a system and method for operating a wind turbine. The method includes measuring, via one or more temperature sensors, a local temperature of a component of the wind turbine for a predetermined time period. The method also includes determining a power capability of the wind turbine as a function of the local temperature. Another step includes measuring, via one or more sensors, a power output of the wind turbine for the predetermined time period. A further step includes determining a power margin of the wind turbine as a function of the power capability and the measured power output and controlling the power output of the wind turbine based, at least in part, on the power margin.

Abstract: The present disclosure is directed to an automated apparatus and method for testing a crowbar circuit of power converter. The crowbar circuit includes an anti-parallel diode and a voltage-controlled switching element, e.g. a silicon-controlled rectifier (SCR). The method includes implementing a first test sequence for testing operability of the diode and a second test sequence for testing operability of the voltage-controlled switching element. More specifically, the first test sequence determines a first current-voltage feedback that is indicative of the operability of the diode and the second test sequence determines a second current-voltage feedback that is indicative of the operability of the voltage-controlled switching element.

Abstract: The present subject matter is directed to a system and method for operating a wind turbine. The method includes measuring, via one or more temperature sensors, a local temperature of a component of the wind turbine for a predetermined time period. The method also includes determining a power capability of the wind turbine as a function of the local temperature. Another step includes measuring, via one or more sensors, a power output of the wind turbine for the predetermined time period. A further step includes determining a power margin of the wind turbine as a function of the power capability and the measured power output and controlling the power output of the wind turbine based, at least in part, on the power margin.

Abstract: Systems and methods for controlling a wind turbine are provided. An operating limit for a component of the wind turbine can be determined based on various environmental conditions (e.g. temperature, altitude, air density, wind speed, etc.) using a de-rating scheme. The operating limit determined using the de-rating scheme can be limited based on a rated operational limit for the at least one component as specified, for instance, by the manufacturer of the component. The wind turbine can be controlled based on the operating limit. For instance, an operating condition of the wind turbine can be controlled so as that operation of the wind turbine does not cause an operational parameter (e.g. an electrical current) to exceed the operating limit determined for the component of the wind turbine.

Abstract: Renewable energy power systems, DC to DC converters, and methods for operating energy storage systems are provided. A system includes a power converter having a DC bus, and an energy storage system coupled to the DC bus of the power converter. The energy storage system includes an energy storage device and a switching power supply coupled between the energy storage device and the DC bus of the power converter. The switching power supply includes a plurality of switching elements, and an energy storage device protection circuit coupled between the plurality of switching elements and the energy storage device, the energy storage device protection circuit including a solid state switch. The switching power supply further includes a fuse coupled to the energy storage device protection circuit.

Abstract: In one aspect, a method for controlling a dual-fed induction generator (DFIG) during a high-voltage grid event is provided. The method includes setting, by a controller, an output of a closed-loop portion of a rotor current regulator to a fixed value such that a predictive feed-forward path sets an internal voltage for the DFIG; and detecting, by the controller, a condition of high dc voltage on a dc link or a condition predictive of high dc voltage on the dc link, and in response reduce a rotor torque producing current command to approximately zero, wherein the dc link connects a line-side converter connected to a system bus and a rotor-side converter connected to a rotor of the DFIG.

Abstract: A wind turbine system is provided. In various embodiments, the system includes a nacelle supported by a tower. At least one rotor blade is rotatably connected with the nacelle to capture wind energy. The at least one rotor blade rotates relative to the nacelle for generating electricity. A generator is coupled to the nacelle for converting the wind energy into electrical energy. A transformer-converter assembly comprises a converter and a transformer such that the converter is integrally connected to the transformer. An electrical and control module is electronically coupled to the generator and the transformer-converter assembly.

Abstract: In one aspect, a method for controlling the operation of switching elements contained within a single-phase bridge circuit of a power convertor may include monitoring gate voltages of a first switching element and a second switching element of the single-phase bridge circuit and controlling the first and second switching elements so that each switching element is alternated between an activated state and a deactivated state. In addition, the method may include transmitting a gating command signal to adjust the first switching element from the deactivated state to the activated state when: a first gate drive command is received that is associated with switching the first switching element to the activated state; a second gate drive command is received that is associated with switching the second switching element to the deactivated state; and the gate voltage of the second switching element is less than a predetermined voltage threshold.

Abstract: System and methods for optimizing operation of a wind turbine are disclosed. In one aspect, the method also includes determining, via a converter controller of a power converter, a tap position of a tap changer configured between the power grid and a primary winding of a transformer. Another step includes calculating, via the converter controller, a primary voltage of the primary winding as a function of the tap position. The method also includes implementing, via the converter controller, a control action if the primary voltage or a measured secondary voltage of a secondary winding of the transformer is outside of a predetermined voltage range.

Abstract: Systems and methods for reducing current imbalance between parallel bridge circuits used in a power converter of a power generation system, such as a wind driven doubly fed induction generator (DFIG) system, are provided. The power converter can include a plurality of bridge circuits coupled in parallel to increase the output power capability of the system. Each of the bridge circuits can include a pair of switching elements, such as insulated gate bipolar transistors (IGBTs), coupled in series with one another. The switching elements of the parallel bridge circuits can be controlled, for instance, using control commands (e.g. pulse width modulation commands) according to a substantially non-interleaved switching pattern. The timing of the control commands according to the substantially non-interleaved switching pattern can be adjusted to reduce current imbalance between the parallel bridge circuits.

Abstract: In one aspect, a method for protecting one or more electrical machines during a grid fault on an electrical system connected with the one or more electrical machines is provided. The method includes detecting a grid fault on an electrical system; taking one or more first actions from a first set of actions based on detected grid fault on the electrical system; detecting at least one operating condition of the electrical system after taking one or more first actions from the first set of actions based on the detected grid fault on the electrical system; and taking one or more second actions from a second set of actions based on the detected at least one operating condition of the electrical system.

Abstract: A method and apparatus for testing operability of a power converter with an existing power conversion assembly of a renewable energy system is disclosed. The method includes transferring a first pulse of energy from an existing power conversion assembly to a power filter of the power converter through first cells within a bridge circuit of the power converter. Another step includes determining a first current-voltage feedback associated with the first pulse. A next step includes transferring a second pulse of energy from the power filter to the existing power conversion assembly through second cells within the bridge circuit such that a portion of the first pulse moves back to the existing power conversion assembly. Another step includes determining a second current-voltage feedback associated with the second pulse. The first and second current-voltage feedbacks are compared with nominal tolerances of the power converter to ensure the power converter is operating properly.