Patents by Inventor Ramakrishnan Krishna
Ramakrishnan Krishna has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9822764Abstract: An automatic adjustment system for a variable-speed wind turbine is provided, having a power vector generator for generating a power vector (Pvec) of wind turbine output power; a mapping unit for establishing relationships (?vec, ?vec) between wind turbine output power and rotational speed and pitch angle on the basis of the power vector (Pvec) and an operational trajectory of the wind turbine; a wind speed estimator for estimating a wind speed (vest); an available power calculator for calculating the available power (Pest) of the wind turbine on the basis of the estimated wind speed (vest) and the established relationships (?vec, ?vec). A method of performing automatic analysis of a wind turbine configuration, a computer program product for carrying out the steps of such a method, and a wind turbine having such an automatic adjustment system are also provided.Type: GrantFiled: October 5, 2014Date of Patent: November 21, 2017Assignee: SIEMENS AKTIENGESELLSCHAFTInventors: Thomas Esbensen, Ramakrishnan Krishna, Frank Scheurich, Michael Stoettrup
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Patent number: 9611834Abstract: A method of controlling a wind turbine having a rotor to which at least one rotor blade is connected, is provided herein. The method includes operating the rotor according to a first rotational speed reference; and operating the rotor according to a second rotational speed reference above the first rotational speed reference, if a fluctuation of an actual rotational speed of the rotor decreases below a fluctuation threshold and/or if a blade pitch angle of the rotor blade increases above a blade pitch angle threshold. The method may further include wherein the rotor is operated according to the first rotational speed reference, if the fluctuation of an actual rotational speed of the rotor increases above another fluctuation threshold which is above the fluctuation threshold and/or if the blade pitch angle of the rotor blade decreases below another blade pitch angle threshold which is below the blade pitch angle threshold.Type: GrantFiled: March 21, 2013Date of Patent: April 4, 2017Assignee: Siemens AktiengesellschaftInventors: Thomas Esbensen, Ramakrishnan Krishna
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Patent number: 9249779Abstract: A method for controlling a wind turbine with a rotor and at least one rotor blade, and a control unit are disclosed. The method is characterized in adjusting a pitch angle of the rotor blade and determining the limit of an input value based on the adjusted pitch angle, wherein the input value includes information about the turbine rotational speed.Type: GrantFiled: December 18, 2012Date of Patent: February 2, 2016Assignee: SIEMENS AKTIENGESELLSCHAFTInventors: Martin Huus Bjerge, Per Egedal, Gustav Hoegh, Ramakrishnan Krishna, Hans Laurberg
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Patent number: 9189755Abstract: A method of determining an estimated wind speed of a wind driving a wind turbine includes measuring a current power generated by the wind turbine, measuring a current rotor speed of a rotor of the wind turbine, and measuring a current blade pitch angle of a rotor blade of the rotor. Moreover, the method includes determining the estimated wind speed based on the current power, the current rotor speed and the current blade pitch angle.Type: GrantFiled: September 22, 2009Date of Patent: November 17, 2015Assignee: SIEMENS AKTIENGESELLSCHAFTInventor: Ramakrishnan Krishna
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Publication number: 20150226183Abstract: A method of controlling a wind turbine having a rotor to which at least one rotor blade is connected, is provided herein. The method includes operating the rotor according to a first rotational speed reference; and operating the rotor according to a second rotational speed reference above the first rotational speed reference, if a fluctuation of an actual rotational speed of the rotor decreases below a fluctuation threshold and/or if a blade pitch angle of the rotor blade increases above a blade pitch angle threshold. The method may further include wherein the rotor is operated according to the first rotational speed reference, if the fluctuation of an actual rotational speed of the rotor increases above another fluctuation threshold which is above the fluctuation threshold and/or if the blade pitch angle of the rotor blade decreases below another blade pitch angle threshold which is below the blade pitch angle threshold.Type: ApplicationFiled: March 21, 2013Publication date: August 13, 2015Applicant: Siemens AktiengesellschaftInventors: Thomas Esbensen, Ramakrishnan Krishna
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Publication number: 20150097373Abstract: An automatic adjustment system for a variable-speed wind turbine is provided, having a power vector generator for generating a power vector (Pvec) of wind turbine output power; a mapping unit for establishing relationships (?vec, ?vec) between wind turbine output power and rotational speed and pitch angle on the basis of the power vector (Pvec) and an operational trajectory of the wind turbine; a wind speed estimator for estimating a wind speed (vest); an available power calculator for calculating the available power (Pest) of the wind turbine on the basis of the estimated wind speed (vest) and the established relationships (?vec, ?vec). A method of performing automatic analysis of a wind turbine configuration, a computer program product for carrying out the steps of such a method, and a wind turbine having such an automatic adjustment system are also provided.Type: ApplicationFiled: October 5, 2014Publication date: April 9, 2015Applicant: SIEMENS AKTIENGESELLSCHAFTInventors: Thomas Esbensen, Ramakrishnan Krishna, Frank Scheurich, Michael Stoettrup
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Patent number: 8897922Abstract: A method for controlling the operation of a wind farm with a plurality of wind turbines is disclosed A setpoint vector is defined, wherein each component of the setpoint vector represents an individual power setpoint of one of the plurality of wind turbines. A dependency matrix, which reflects a desired power generation distribution between different wind turbines of the plurality of wind turbines, is determined. A power reference vector is calculated by multiplying the dependency matrix with the setpoint vector, such that the power reference vector comprises a coordinated power setpoint for each wind turbine. The operation of the wind farm is controlled based on the calculated power reference vector. A superordinate control system, a wind farm, a computer-readable medium and a program element, which are adapted for performing and/or for controlling the above described wind farm operation control method are further disclosed.Type: GrantFiled: January 18, 2011Date of Patent: November 25, 2014Assignee: Siemens AktiengesellschaftInventors: Per Egedal, Ramakrishnan Krishna
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Publication number: 20140025788Abstract: A system may include a discovery engine to perform a discovery process on a network of multiple configuration items and to populate a data structure with information about each discovered configuration item in the network. The information may include a configuration parameter for each configuration item and a metric to be monitored for the configuration item.Type: ApplicationFiled: July 18, 2012Publication date: January 23, 2014Inventors: Ramakrishnan Krishna MAHADEVAN, Pargaonkar VISHWANATH
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Publication number: 20130187383Abstract: It is described an arrangement for determining a target value of an operational variable of a wind turbine, the arrangement comprising: at least one input terminal for receiving at least one operational parameter of the wind turbine; a determining unit adapted to determine a target value of an operational variable of the wind turbine based on the operational parameter. Further, a corresponding method and a wind turbine are described.Type: ApplicationFiled: July 31, 2012Publication date: July 25, 2013Inventors: Thomas Esbensen, Gustav Hoegh, Ramakrishnan Krishna
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Publication number: 20130161952Abstract: A method for controlling a wind turbine with a rotor and at least one rotor blade, and a control unit are disclosed. The method is characterised in adjusting a pitch angle of the rotor blade and determining the limit of an input value based on the adjusted pitch angle, wherein the input value includes information about the turbine rotational speed.Type: ApplicationFiled: December 18, 2012Publication date: June 27, 2013Inventors: Martin Huus Bjerge, Per Egedal, Gustav Hoegh, Ramakrishnan Krishna, Hans Laurberg
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Publication number: 20130156577Abstract: A method of controlling a wind turbine is provided. The method includes the steps of obtaining a number of operating values relevant to a wind turbine, calculating a thrust setpoint on the basis of the operating values, and controlling a wind turbine according to a thrust setpoint. A wind park controller, a wind turbine controller, and a wind park are also provided.Type: ApplicationFiled: November 30, 2012Publication date: June 20, 2013Inventors: Thomas Esbensen, Gustav Hoegh, Ramakrishnan Krishna
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Publication number: 20120078518Abstract: A method of determining an estimated wind speed of a wind driving a wind turbine includes measuring a current power generated by the wind turbine, measuring a current rotor speed of a rotor of the wind turbine, and measuring a current blade pitch angle of a rotor blade of the rotor. Moreover, the method includes determining the estimated wind speed based on the current power, the current rotor speed and the current blade pitch angle.Type: ApplicationFiled: September 22, 2009Publication date: March 29, 2012Inventor: Ramakrishnan Krishna
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Publication number: 20110175353Abstract: A method for controlling the operation of a wind farm with a plurality of wind turbines is disclosed A setpoint vector is defined, wherein each component of the setpoint vector represents an individual power setpoint of one of the plurality of wind turbines. A dependency matrix, which reflects a desired power generation distribution between different wind turbines of the plurality of wind turbines, is determined. A power reference vector is calculated by multiplying the dependency matrix with the setpoint vector, such that the power reference vector comprises a coordinated power setpoint for each wind turbine. The operation of the wind farm is controlled based on the calculated power reference vector. A superordinate control system, a wind farm, a computer-readable medium and a program element, which are adapted for performing and/or for controlling the above described wind farm operation control method are further disclosed.Type: ApplicationFiled: January 18, 2011Publication date: July 21, 2011Inventors: Per Egedal, Ramakrishnan Krishna