Abstract: A method of updating a scene model for a foreground segmentation of an input image captured from a camera, is disclosed. One or more visual elements of the input image are determined. A spatial relationship between at least one of the visual elements and the scene model for a foreground segmentation of the input image is determined. The method updates the scene model for determining the foreground segmentation of the input image based on the determined spatial relationship.

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 determining stability of a camera comprises capturing an image with the camera and then (A) determining a magnitude of motion for each region of a current sub-division of the image. A step (B) then determines a number of the magnitudes of motion not larger than a magnitude threshold associated with the current sub-division, and where the determined number is greater than or equal to a region threshold associated with the number of regions in the current sub-division, (i) determining the camera to be stable, or otherwise (ii) dividing the current sub-division of the image into a further sub-division and repeating steps (A) and (B) upon the further sub-division.

Abstract: A method of operating a wind turbine is disclosed, the wind turbine comprising a power generator, a machine-side converter connected to the power generator, a line-side converter connected to a power grid through associated power components, and a DC-link connected between the machine-side converter and the line-side converter. The method includes monitoring the power grid for overvoltage events, and upon detecting an overvoltage event: (1) disabling active operation of the machine-side converter and the line-side converter, (2) enabling an AC load dump connected between the machine side converter and the power generator in order to dissipate power output from the power generator, (3) waiting for a waiting period, and (4) enabling active operation of the line-side converter and the machine converter when the overvoltage event ends within the waiting period.

Abstract: According to an embodiment, a method of operating a wind turbine comprising a DC-to-AC voltage converter is provided, the wind turbine being connectable to a grid via the DC-to-AC voltage converter, the method comprising: determining a line voltage of a power line connecting the DC-to-AC voltage converter to the grid; if the determined line voltage exceeds a predefined voltage threshold value, injecting reactive current into the power line, wherein the amount of reactive current injected is chosen such that an output voltage of the DC-to-AC voltage converter is kept within a predetermined voltage range.

Abstract: A wind turbine is provided. The wind turbine includes a generator, an output thereof being connectable to a power grid via a power transmission path, the power transmission path comprising a generator side converter coupled to the output of the generator, a grid side converter coupled to the power grid, and a DC link coupled between the generator side converter and the grid side converter. For diverting the generator power, a load dump arrangement is provided which includes at least one resistor, a plurality of switches, and a plurality of electrical connections which electrically connect the at least one resistor to the output of the generator and across the DC link via the plurality of switches. One common and configurable load dump is used for both converter system failures and grid failures. As compared to two separate load dumps for converter failures and grid failures, the single load dump will require a smaller space for a wind turbine.

Abstract: A wind turbine generator is disclosed herein. In a described embodiment, the wind turbine generator comprises an electrical generator 101 configured to generate AC signals, a plurality of power converters 110,112,111 operated by a gating signal with each power converter configured to convert the AC signals from the electrical generator 101 into fixed frequency AC signals. The wind turbine generator further comprises a controller configured to enter a fault mode when a grid voltage falls outside an acceptable threshold, and during the fault mode the controller is configured to provide a reactive current reference dependant on a grid voltage distant from the wind turbine generator. A method of controlling a wind turbine generator is also disclosed.

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: Disclosed are a method and apparatus for adjusting a set of luminance values associated with a set of visual elements in a current frame (310) of a video sequence for object detection (370). The method determines (410,430,450), for each of a plurality of scenarios (SO, SI, S2), a set of adjusted luminance values based on a corresponding luminance compensation value, and accumulates (460), for each scenario, a set of brightness counts and darkness counts of the current frame based on the set of adjusted luminance values. A metric (470) is calculated for each scenario based on the set of brightness counts and darkness counts and one of scenarios is selected based on the calculated metric. The method then selects (350) the adjusted luminance value associated with the selected scenario as an adjusted set of luminance values associated with the current frame of the video sequence.

Abstract: Disclosed herein are a system and method for performing foreground/background separation on an input image. The method pre-classifies (1010, 1020) an input visual element in the input image as one of a first element type and a second element type, dependent upon a predetermined characteristic. The method performs a first foreground/background separation (1030) on the input visual element that has been pre-classified as the first element type, wherein the first foreground/background separation step is based on color data and brightness data of the input visual element. The method performs a second foreground/background separation (1040) on the input visual element that has been pre-classified as the second element type, wherein the second foreground/background separation step is based on color data, brightness data, and texture of the input visual element.

Abstract: A memory device that accurately tracks memory operations includes a vertical loopback for tracking a sense clock signal to a row address decoder, and read and write reference bit lines in a reference column that include loopbacks for vertically tracking a selected bit line during read and write operations. Preferably the widths of word lines and a sense line are equal to enable the sense line to horizontally track any selected word line. The memory device also includes tri-state input/output (I/O) latches to latch sense amplifier outputs. A drive circuit of the tri-state I/O latch is disabled when the output is available at the corresponding sense amplifier and enabled when the output is latched by the latch circuit.

Abstract: A power dissipating arrangement for dissipating power from a generator in a wind turbine is provided. The generator comprises a plurality of output terminals corresponding to a multi-phase output. The power dissipating arrangement comprises a plurality of dissipating units, a plurality of semiconductor switches, a trigger circuit for switching the semiconductor switches and a control unit for controlling the operation of the trigger circuit, thereby controlling the switching of the semiconductor switches. Each dissipating unit includes a first terminal and a second terminal. The first terminal of each dissipating unit is coupled to each output terminal of the generator. Each semiconductor switch includes a first terminal anode, a second terminal and a gate terminal.

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: A system for detecting soft errors in a memory device includes a latch, a master flip-flop and a slave flip-flop. The latch receives input data (control and/or address signals) at the beginning of a memory operation in response to a rising edge of a first clock signal. The output of the latch is provided to the master flip-flop. The master flip-flop continuously receives and stores the latch output during the memory operation based on a second clock signal. The slave flip-flop receives and stores the output of the master flip-flop at the end of the memory operation based on the second clock signal. A comparator compares the input data with the output of the slave flip-flop to detect soft errors that occur during the memory operation.

Abstract: A method of segmenting an image into foreground and background regions, is disclosed. The image is divided into a plurality of blocks. The plurality of blocks comprises at least a first block of a first size and a second block of a second size. A first plurality of mode models of the first size for the first block and a second plurality of mode models of the second size for the second block are received. If foreground activity in the first block is higher than the foreground activity in the second block, the first size is smaller than the second size. The image is segmented into foreground and background regions based on the received mode models.

Abstract: A memory device that accurately tracks memory operations includes a vertical loopback for tracking a sense clock signal to a row address decoder, and read and write reference bit lines in a reference column that include loopbacks for vertically tracking a selected bit line during read and write operations. Preferably the widths of word lines and a sense line are equal to enable the sense line to horizontally track any selected word line. The memory device also includes tri-state input/output (I/O) latches to latch sense amplifier outputs. A drive circuit of the tri-state I/O latch is disabled when the output is available at the corresponding sense amplifier and enabled when the output is latched by the latch circuit.

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 controller arrangement of an electrical power transfer system (1) of a wind turbine is described. The wind turbine has an electrical generator and is connected to an electrical power grid, wherein the power transfer system (1) is arranged to transfer electrical power from the generator to the grid. The power transfer system (1) has at least two electrical elements (2-6), e.g. converters, and at least two controllers (15-17) each arranged to control at least one element (2-6).

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 power conversion system for converting electrical power from at least one power source includes a plurality of converter chains which couple the at least one power source to at least one load. At least two of the converter chains comprise an associated dissipating unit. The dissipating units are coupled via at least one switch. A controller is arranged to control the at least one switch to route power to be dissipated from one of the converter chains to the converter chain's associated dissipating unit, or to at least one of the other dissipating units, or to the converter chain's associated dissipating unit and to at least one of the other dissipating units, to cause corresponding dissipation of the power to be dissipated.