The Experts below are selected from a list of 224115 Experts worldwide ranked by ideXlab platform
Hee-sang Ko - One of the best experts on this subject based on the ideXlab platform.
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modeling and control of pmsg based variable speed wind turbine
Electric Power Systems Research, 2010Co-Authors: Hee-sang KoAbstract:This chapter presents a control scheme of a variable-speed wind turbine with a permanent-magnet synchronous-generator (PMSG) and full-scale back-to-back voltage source converter. A comprehensive dynamical model of the PMSG wind turbine and its control scheme is presented. The control scheme comprises both the wind-turbine control itself and the power-converter control. In addition, since the PMSG wind turbine is able to support actively the grid due to its capability to control independently active and reactive power production to the imposed set-values with taking into account its Operating State and limits, this chapter presents the supervisory reactive-power control scheme in order to regulate/contribute the voltage at a remote location. The ability of the control scheme is assessed and discussed by means of simulations, based on a candidate site of the offshore wind farm in Jeju, Korea.
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modeling and control of dfig based variable speed wind turbine
Electric Power Systems Research, 2008Co-Authors: Hee-sang Ko, Gi Gab Yoon, Namho Kyung, Wonpyo HongAbstract:This paper presents a modeling and a control of doubly fed induction-generator (DFIG)-based variable-speed wind-turbine. A detail dynamic model of a DFIG-based wind-turbine grid-connected system is presented in the dq-synchronous reference frame. Along with conventional control schemes for wind turbine, an innovative voltage control scheme is proposed that manipulates dynamically the reactive power from the voltage-source converter (VSC) with taking into account its Operating State and limits.
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Active use of DFIG-based variable-speed wind-turbine for voltage regulation at a remote location
IEEE Transactions on Power Systems, 2007Co-Authors: Hee-sang Ko, Gi Gab YoonAbstract:Renewable energy sources are presently exempted from control functions. This, in turn, simplifies the requirements for the renewable energy source interconnection as well as the project developer, allowing connection to the system without having to take part in the overall stabilization effort. Thus, in order to maintain the power generation and consumption balance, necessary for stable functioning of the power system, the traditional power plants always exert necessary control actions. However, the present practice requires the independent power producers and/or generators who want to connect to the grid to meet the so-called connection requirements of the local electric utility (the grid company). Therefore, this paper proposes an innovative reactive power control scheme for voltage regulation at a remote location that manipulates dynamically the reactive power from the voltage source converter (VSC) with taking into account its Operating State and limits.
Gi Gab Yoon - One of the best experts on this subject based on the ideXlab platform.
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modeling and control of dfig based variable speed wind turbine
Electric Power Systems Research, 2008Co-Authors: Hee-sang Ko, Gi Gab Yoon, Namho Kyung, Wonpyo HongAbstract:This paper presents a modeling and a control of doubly fed induction-generator (DFIG)-based variable-speed wind-turbine. A detail dynamic model of a DFIG-based wind-turbine grid-connected system is presented in the dq-synchronous reference frame. Along with conventional control schemes for wind turbine, an innovative voltage control scheme is proposed that manipulates dynamically the reactive power from the voltage-source converter (VSC) with taking into account its Operating State and limits.
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Active use of DFIG-based variable-speed wind-turbine for voltage regulation at a remote location
IEEE Transactions on Power Systems, 2007Co-Authors: Hee-sang Ko, Gi Gab YoonAbstract:Renewable energy sources are presently exempted from control functions. This, in turn, simplifies the requirements for the renewable energy source interconnection as well as the project developer, allowing connection to the system without having to take part in the overall stabilization effort. Thus, in order to maintain the power generation and consumption balance, necessary for stable functioning of the power system, the traditional power plants always exert necessary control actions. However, the present practice requires the independent power producers and/or generators who want to connect to the grid to meet the so-called connection requirements of the local electric utility (the grid company). Therefore, this paper proposes an innovative reactive power control scheme for voltage regulation at a remote location that manipulates dynamically the reactive power from the voltage source converter (VSC) with taking into account its Operating State and limits.
Juan Carlos Garciaprada - One of the best experts on this subject based on the ideXlab platform.
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emd based methodology for the identification of a high speed train running in a gear Operating State
Sensors, 2018Co-Authors: Alejandro Bustos, Higinio Rubio, Cristina Castejon, Juan Carlos GarciapradaAbstract:An efficient maintenance is a key consideration in systems of railway transport, especially in high-speed trains, in order to avoid accidents with catastrophic consequences. In this sense, having a method that allows for the early detection of defects in critical elements, such as the bogie mechanical components, is a crucial for increasing the availability of rolling stock and reducing maintenance costs. The main contribution of this work is the proposal of a methodology that, based on classical signal processing techniques, provides a set of parameters for the fast identification of the Operating State of a critical mechanical system. With this methodology, the vibratory behaviour of a very complex mechanical system is characterised, through variable inputs, which will allow for the detection of possible changes in the mechanical elements. This methodology is applied to a real high-speed train in commercial service, with the aim of studying the vibratory behaviour of the train (specifically, the bogie) before and after a maintenance operation. The results obtained with this methodology demonstrated the usefulness of the new procedure and allowed for the disclosure of reductions between 15% and 45% in the spectral power of selected Intrinsic Mode Functions (IMFs) after the maintenance operation.
Christopher Kreis - One of the best experts on this subject based on the ideXlab platform.
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method and device for detecting an Operating State of a steering wheel in a vehicle
2010Co-Authors: Roland Greul, Alexander Gaedke, Christopher KreisAbstract:In order to detect the Operating State (hands_off, hands_on) of a steering wheel in a vehicle, the invention proposes for a current, high resolution steering wheel angle and a current steering moment to be determined. Depending on the steering wheel angle and the steering moment, a driver manual moment (TLR) currently applied by the driver is determined. Depending on a curve of the driver manual moment (TLR), the Operating State (hands_off, hands_on) of the steering wheel is then determined or it is detected whether the driver has the hands on the steering wheel (hands_on) or whether the driver has removed the hands from the sterling wheel (hands_off). The method according to the invention can be carried out using the sensors already provided in an EPS system.
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method and apparatus for detecting an Operating condition of a steering wheel in a vehicle
2009Co-Authors: Alexander Gaedke, Roland Greul, Christopher KreisAbstract:To the Operating State (hands_off, hands_on) to detect a steering wheel in a vehicle, it is proposed that a current, high-resolution steering wheel angle and an actual steering torque are determined. Depending on the steering wheel angle and the steering torque, a current applied by the driver the driver manual torque (T In response to a history of the driver's manual torque (T
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verfahren und vorrichtung zum erkennen eines bedienzustands eines lenkrads in einem fahrzeug method and apparatus for detecting an Operating condition of a steering wheel in a vehicle
2009Co-Authors: Alexander Gaedke, Roland Greul, Christopher KreisAbstract:Um den Bedienzustand (hands_off, hands_on) eines Lenkrads in einem Fahrzeug zu erkennen, wird vorgeschlagen, dass ein aktueller, hoch aufgeloster Lenkradwinkel und ein aktuelles Lenkmoment bestimmt werden. To the Operating State (hands_off, hands_on) of a steering wheel in a vehicle to recognize, it is proposed that a current, high-resolution steering wheel angle and a current steering torque can be determined. In Abhangigkeit von dem Lenkradwinkel und dem Lenkmoment wird ein von dem Fahrer aktuell aufgebrachtes Fahrerhandmoment (T LR ) bestimmt. Depending on the steering wheel angle and the steering torque of the driver, a current driver's hand-applied torque (T LR) is determined. In Abhangigkeit von einem Verlauf des Fahrerhandmoments (T LR ) wird dann der Betriebszustand (hands_off, hands_on) des Lenkradss bestimmt bzw. es wird erkannt, ob der Fahrer die Hande am Lenkrad hat (hands_on oder ob der Fahrer die Hande von dem Lenkrad genommen hat (hands_off). Das erfindungsgemase Verfahren kann mit der in einer EPS-Lenkung bereits vorhandenen Sensorik durchgefuhrt werden. In response to a history of the driver's manual torque (T LR) is then the Operating State (hands_off, hands_on) of Lenkradss determined and it is detected whether the driver has his hands on the steering wheel (hands_on or if the driver has taken his hands from the steering wheel (hands_off). The process can be carried out with the already present in an EPS steering sensors.
S S Choi - One of the best experts on this subject based on the ideXlab platform.
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control of a solid oxide fuel cell power plant in a grid connected system
IEEE Transactions on Energy Conversion, 2007Co-Authors: Sumedha Rajakaruna, S S ChoiAbstract:The fastest and yet most prudent ways of changing the output power level of a solid oxide fuel cell power plant connected to the ac-grid are explored. The Operating State of the fuel cell power plant is examined in term of the concept of feasible Operating area of a cell. The utilization factor of the cell stack is maintained constant in steady-State by feeding natural gas to the fuel processor at a rate proportional to the current drawn from the stack. The fluctuations of the utilization factor in the transient State due to a change in Operating power level can be constrained to the allowable range by strategically controlling the current drawn by the power conditioning unit. Based on measured variables and dynamic characteristics of the fuel processor, four strategies of controlling current are compared to arrive at the strategy that results in minimum transient time for a given power change. The proposed control schemes are verified through computer simulations.