Abstract: A method of operating a wind turbine plant is provided. Such a wind turbine plant comprises at least one transmission branch comprising a plurality of wind turbine generators and coupled to an electrical grid at a point of common coupling through at least one circuit breaker comprising a breaking capacity. The method comprises monitoring the electrical grid for a low voltage fault event; and if a low voltage fault event is detected: calculating a grid short circuit strength, determining a short circuit current limit if the grid short circuit strength requires an initial fault current contribution which exceeds the breaking capacity of the circuit breaker to be passed through the circuit breaker, determining a maximum fault current contribution based on the short circuit current limit and operating the wind turbine generators to provide to the electrical grid the maximum fault current contribution.

Abstract: A variable speed wind turbine is provided. The wind turbine comprises a generator, a power converter for converting at least a portion of electrical power generated by the generator, an energy management arrangement coupled to the power converter, the energy management arrangement comprises an energy storage unit, and a controller. The controller is adapted to detect a power imbalance event and to transfer at least a portion of excess electrical energy generated by the generator to the energy storage unit to be stored therein when the power imbalance event is detected.

Abstract: A method of operating a wind turbine is provided. The wind turbine comprises a turbine rotor with at least one blade having a variable pitch angle, a power generator, and a power converter connected to the power generator via a first circuit breaker and to a power grid via a second circuit breaker. According to the method, overvoltage events at the power grid are monitored. If an overvoltage event is detected, the method comprises opening the first circuit breaker and the second circuit breaker, disabling active operation of the power converter, connecting a power dissipating unit to the power generator to dissipate power output from the power generator, and moving the pitch angle of the at least one blade towards a feathered position.

Abstract: A method of controlling an inverter, in which the inverter includes a single-phase inverter arrangement comprising a complementary pair of power switches, comprises the steps of: controlling the complementary pair of power switches with a modulating signal to output an AC signal; judging which of the power switches in the complementary pair of power switches is at a higher temperature; determining the magnitude and sign of a DC offset signal to apply to the modulating signal to reduce the total current in the power switch judged to be at the higher temperature; and applying the DC offset signal to the modulating signal.

Abstract: A method of detecting rotor and/or stator side faults in an induction motor. Signals indicative of three-phase stator currents of the induction motor are acquired (10) and converted (16) into three-phase current phasors. The three-phase current phasors are combined (16) to obtain a quantity having a DC component and an AC component.

Abstract: Parameters of PM machines, especially for IPM machine, are known to vary by significant amounts. This affects the controllability of such machines, which may lead to reduced power loading capability and increased losses. The present invention relates to a method for PM machine inductance profile identification based on voltage mode stator flux observation which could be easily integrated to the generator start-up process in wind turbine application for both stator flux vector feedback control system and current vector feedback control system.

Abstract: A method for controlling a wind power plant, the wind power plant including a plant controller for controlling a plurality of wind turbine generators. The method for controlling a wind power plant allows the wind power plant to continue operating through a grid fault in a weak grid environment. In the method, a fault recovery process is carried out with a wind turbine power controller during a wind turbine fault recovery state to determine a grid voltage (VWTG), compare the grid voltage to a predetermined reference voltage (Vref) to obtain a difference value, and determine a current reference (QrefVC) based on the difference value for generating a reactive current (Idref) for regulating the grid voltage to the predetermined reference grid voltage. A corresponding wind power plant is further provided.

Abstract: A method for operating a power generation system coupled to a power grid during a grid unbalance event, a method for determining an injection current to be supplied into a power grid by a power generation system, and a method for addressing an asymmetric grid fault in a power grid connected to a power generation system are provided. The methods may be carried out based on a reactive or an active power/current priority.

Abstract: The invention concerns the damping of torsional oscillations/vibrations, particularly during electrical power generation within a gas turbine such as a civil aviation engine. The method of the invention relies on actively generating compensating oscillations in a driveline of a system to actively damp undesirable oscillations existing in the system.

Abstract: A method of open-switch fault detection in a two-level voltage source power converter comprises the steps of: i. acquiring the waveforms of three-phase alternating current of the two-level voltage source power converter; ii. calculating at least a first time derivative of each acquired waveform; and iii. using the at least first time derivatives to determine whether an open-switch fault is present in the two-level voltage source power converter.

Abstract: A wind turbine includes a grid side converter coupled to a grid via a power line. The method includes determining a first active power reference and a first reactive power reference indicating a requested amount of active power and reactive power, respectively, depending on at least a wind turbine operation strategy; determining a positive and negative sequence components of a grid voltage; determining indications of an actual amount of active power and reactive power to be supplied by the grid side converter to the grid, respectively; generating a parameters defining a proportion of positive sequence current component and negative sequence current component to be injected by the grid side converter in order to supply active power and reactive power; and supplying, with the grid side converter, active and reactive power to the power line based on the current reference.

Abstract: A method for classifying a visual element in a video frame as either foreground or background, the video frame being characterised using a scene model comprising a plurality of modes, the method comprising the steps of: determining a blob boundary characteristic for a blob comprising at least the visual element; identifying a mode matched to the visual element; classifying the visual element and the matched mode as foreground dependent upon a match mode boundary characteristic of the matched mode; and updating the scene model dependent upon the blob boundary characteristic and the matched mode boundary characteristic.

Abstract: A weight management mat for passively and automatically monitoring weight for one or more individuals in a household. The weight management mat generally includes a housing having an upper mat and a lower mat between which is sealed a pair of perpendicular sensor arrays. Each sensor array includes fiber optic cables laid out in a grid pattern. One or more microbend inducers act to induce detectable microbends in the fiber optic cables when an individual steps on the upper mat. The change in light intensity caused by these microbends is recorded by photodetectors and processed by a microcontroller. The present invention may be utilized to identify each unique individual stepping on the present invention by the pressure map of their feet. Thus, recorded weight measurements may be tracked to aid in weight management.

Abstract: An approach is provided for battery management in route navigation. A battery management module determines a request to calculate at least one navigation route. The battery module then determines battery charging information associated with presenting guidance information via at least one application of at least one device during the at least one navigation route. Further, the battery management module causes, at least in part, a presentation of the battery charging information on at least one user interface of the at least one device. In one embodiment, the charging information can be updated based on selecting one or more segments of the at least one navigation route to hibernate. In yet another embodiment, alternative content that is less battery intensive can be presented during the hibernated segments in place of active navigation information.

Abstract: A variable speed wind turbine is provided. The variable speed wind turbine comprises a generator, a power converter for converting at least a portion of electrical power generated by the generator, the power converter comprising a generator-side converter, a grid-side converter and a DC (direct current) link therebetween, a power dissipating unit operatively coupled to the DC-link, and a controller. The controller is adapted to receive a request to reduce power output from the wind turbine, determine a feed forward power signal based on a reference generator power and a desired turbine power, and operate the power dissipating unit based on the feed forward power signal.

Abstract: Disclosed is a method of classifying visual elements in a region of a video as either foreground or background. The method classifies each visual element in the region as either foreground or background using a first classifier, and expands spatially at least one of the visual elements classified as foreground to form a spatially expanded area. The method then classifies the visual elements in the spatially expanded area as either foreground or background using a second classifier that is more sensitive to foreground than the first classifier.

Abstract: A method of assessing a condition of a multi-phase power system comprises the steps of: acquiring a voltage signal and a current signal for each phase of the multi-phase power system; calculating a product of the voltage signal for each phase of the multi-phase power system with one of the current signals such that the product is between a voltage signal for one phase and a current signal for a different phase for at least two of the products; summing the calculated products; and identifying the possible existence of a fault in the multi-phase power system based on a frequency analysis of the summed calculated products.

Abstract: According to a method of the present invention, a method of operating a wind turbine comprising a power generator, a generator side converter connected to the power generator, a line side converter connected to a power grid through power components, and a DC-link connected between the generator side converter and the line side converter is provided, the method comprising: monitoring the grid voltages on the power grid for overvoltage events; if an overvoltage event is detected, operating the line side converter in an overmodulation range for at least a part of the duration of the overvoltage event.

Abstract: A wind turbine is provided. The wind turbine comprises a generator, a power converter for converting at least a portion of electrical power generated by the generator, an energy dissipating unit and a controller. The power converter comprises a generator-side converter, a grid-side converter and a DC (direct current) link there between. The energy dissipating unit is operatively coupled to the DC-link. The controller is adapted to activate the energy dissipating unit to dissipate energy from the DC-link in response to a shutdown request.

Abstract: The invention relates to a control system for compensating undesired electrical harmonics on an electrical grid. Part of the control system referred to as a harmonic compensator is operatively connected with a power inverter of a power producing unit supplying power to the grid. Another part of the control system, referred to as an impedance detector, is operatively connected to a point of coupling to which point one or more power producing units are connected. The impedance detector is configured to scan impedances as a function of frequency to identify frequencies of impedance peaks which peaks are indicative of resonance frequencies. The determined resonance frequencies are supplied to one or more the harmonic compensators. A compensator determines control signals to the inverter which causes the inverter to inject compensation currents to the grid which currents will damp currents oscillating at or close to the determined resonance frequency.