The Experts below are selected from a list of 9231 Experts worldwide ranked by ideXlab platform
Arne Hejde Nielsen - One of the best experts on this subject based on the ideXlab platform.
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modelling and transient stability of large wind farms
International Journal of Electrical Power & Energy Systems, 2003Co-Authors: Vladislav Akhmatov, Hans Knudsen, Arne Hejde Nielsen, Jorgen Kaas Pedersen, Niels Kjolstad PoulsenAbstract:The paper is dealing with modelling and short-term voltage stability considerations of large wind farms. A physical model of a large offshore wind farm consisting of a large number of Windmills is implemented in the dynamic simulation tool PSS/E. Each Windmill in the wind farm is represented by a physical model of grid-connected Windmills. The Windmill generators are conventional induction generators and the wind farm is ac-connected to the power system. Improvements of short-term voltage stability in case of failure events in the external power system are treated with use of conventional generator technology. This subject is treated as a parameter study with respect to the Windmill electrical and mechanical parameters and with use of control strategies within the conventional generator technology. Stability improvements on the wind farm side of the connection point lead to significant reduction of dynamic reactive compensation demands. In case of blade angle control applied at failure events, dynamic reactive compensation is not necessary for maintaining the voltage stability.
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advanced simulation of Windmills in the electric power supply
International Journal of Electrical Power & Energy Systems, 2000Co-Authors: Vladislav Akhmatov, Hans Knudsen, Arne Hejde NielsenAbstract:An advanced model of a grid-connected Windmill is set up where the Windmill is a complex electro-mechanical system. The Windmill model is implemented as a standardised component in the dynamic simulation tool, PSS/E, which makes it possible to investigate dynamic behaviour of grid-connected Windmills as a part of realistic electrical grid models. This means an arbitrary number of wind farms or single Windmills within an arbitrary network configuration. The Windmill model may be applied to the study of electric power system stability and of power quality as well. It is found that a grid-connected Windmill operates as a low-pass filter, whereby the two following observations are made: (1) interaction between the electrical grid and the mechanical systems of grid-connected Windmills is given by a low frequency oscillation as the result of disturbances in the electric grid; (2) flicker, which is commonly explained by the dynamic wind variation, may also be caused by mechanical eigenswings in the Windmill mechanical construction.
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advanced simulation of Windmills in the electric power supply
International Journal of Electrical Power & Energy Systems, 2000Co-Authors: Vladislav Akhmatov, Hans Knudsen, Arne Hejde NielsenAbstract:An advanced model of a grid-connected Windmill is set up where the Windmill is a complex electro-mechanical system. The Windmill model is implemented as a standardised component in the dynamic simulation tool, PSS/E, which makes it possible to investigate dynamic behaviour of grid-connected Windmills as a part of realistic electrical grid models. This means an arbitrary number of wind farms or single Windmills within an arbitrary network configuration. The Windmill model may be applied to the study of electric power system stability and of power quality as well. It is found that a grid-connected Windmill operates as a low-pass filter, whereby the two following observations are made: (1) interaction between the electrical grid and the mechanical systems of grid-connected Windmills is given by a low frequency oscillation as the result of disturbances in the electric grid; (2) flicker, which is commonly explained by the dynamic wind variation, may also be caused by mechanical eigenswings in the Windmill mechanical construction.
Toshihisa Funabashi - One of the best experts on this subject based on the ideXlab platform.
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sensor less maximum power point tracking control for wind generation system with squirrel cage induction generator
Renewable Energy, 2009Co-Authors: Tomonobu Senjyu, Naomitsu Urasaki, Yasutaka Ochi, Yasuaki Kikunaga, Motoki Tokudome, Atsushi Yona, Endusa Billy Muhando, Toshihisa FunabashiAbstract:This paper proposes a technique that determines the optimal Windmill operation speed and the optimal rotor flux. Moreover, the position and speed sensor-less wind generation system using the electromotive voltage observer to estimate rotor position and full-order observer to estimate rotor speed and the Windmill output torque are proposed. The position and speed sensor-less maximum power point of wind power generation system is controlled by using the above estimated values, optimized Windmill operation speed for maximum output power and optimized rotor flux for minimum generator losses. The effectiveness of the position and speed sensor-less maximum power point tracking control for wind power generation system with squirrel cage induction generator is verified by simulations. The simulation results confirm that the proposed method can estimate the operation speed efficiently.
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output power leveling of wind turbine generator for all operating regions by pitch angle control
IEEE Transactions on Energy Conversion, 2006Co-Authors: Tomonobu Senjyu, Ryosei Sakamoto, Naomitsu Urasaki, Toshihisa Funabashi, H Fujita, Hideomi SekineAbstract:Wind energy is not constant and Windmill output is proportional to the cube of wind speed, which causes the generated power of wind turbine generators (WTGs) to fluctuate. In order to reduce fluctuation, different methods are available to control the pitch angle of blades of Windmill. In a previous work, we proposed the pitch angle control using minimum variance control, and output power leveling was achieved. However, it is a controlled output power for only rated wind speed region. This paper presents a control strategy based on average wind speed and standard deviation of wind speed and pitch angle control using a generalized predictive control in all operating regions for a WTG. The simulation results by using actual detailed model for wind power system show the effectiveness of the proposed method.
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output power leveling of wind turbine generator for all operating regions by pitch angle control
IEEE Power Engineering Society General Meeting 2005, 2005Co-Authors: Ryosei Sakamoto, Tomonobu Senjyu, Naomitsu Urasaki, Toshihisa Funabashi, H Fujita, T Kinjo, Hideomi SekineAbstract:Effective utilization of renewable energies such as wind energy is expected instead of the fossil fuel. Wind energy is not constant and Windmill output is proportional to the cube of wind speed, which cause the generated power of wind turbine generators to fluctuate. In order to reduce fluctuating components, there is a method to control pitch angle of blades of Windmill. We have proposed the pitch angle control using minimum variance control in a previous work. However, it is a controlled output power for only rated wind speed region. This paper presents a control strategy based on average wind speed and standard deviation of wind speed, and pitch angle control using a generalized predictive control in all operating regions for wind turbine generator. The simulation results with using actual detailed model for wind power system show effectiveness of the proposed method.
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output power leveling of wind turbine generator by pitch angle control using adaptive control method
IEEE International Conference on Power System Technology, 2004Co-Authors: Ryosei Sakamoto, Tomonobu Senjyu, Naomitsu Urasaki, T Kinjo, Toshihisa FunabashiAbstract:Effective utilization of renewable energies such as wind energy is expected instead of fossil fuels. Wind energy is not constant and Windmill output is proportional to the cube of wind speed, which cause the generated power of wind turbine generators (WTGs) to fluctuate. In order to reduce fluctuating components, there is a method to control pitch angle of the blades of the Windmill. In this paper, output power leveling of wind turbine generator by pitch angle control using an adaptive control is proposed. A self-tuning regulator (STR) is used as the adaptive control. The control input is determined by the minimum variance control (MVC). It is possible to compensate the influence of parameter variations by using the proposed controller. The simulation results with the actual model for the wind power system show effectiveness of the proposed controller.
Nicole M Bordelon - One of the best experts on this subject based on the ideXlab platform.
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hip range of motion and strength and energy flow during Windmill softball pitching
Journal of Athletic Training, 2021Co-Authors: Gretchen D Oliver, Kyle Wasserberger, Anne De Swart, Kenzie B Friesen, Jessica L Downs, Nicole M BordelonAbstract:Context Inadequate hip range of motion (ROM) and isometric strength (ISO) may interfere with energy flow through the kinetic chain and result in increased injury susceptibility. Objective To examine the relationship of hip ROM and ISO with energy flow through the trunk and pitching-arm segments during the Windmill softball pitch in youth athletes. A subsequent purpose was to examine the relationship between energy flow and pitch speed. Design Descriptive laboratory study. Setting University research laboratory. Patients or other participants A sample of 29 youth softball pitchers (age = 11.2 ± 1.3 years, height = 155.0 ± 10.4 cm, mass = 53.2 ± 12.6 kg). Main outcome measure(s) Bilateral hip internal-rotation and external-rotation (ER) ROM and ISO were measured. Net energy outflow and peak rates of energy outflow from the distal ends of the trunk, humerus, and forearm were calculated for the acceleration phase of the Windmill softball pitch, and pitch speed was measured. Results Regression analysis revealed an effect of drive-hip ER ISO on the net energy flow out of the distal ends of the trunk (P = .045) and humerus (P = .002). Specifically, increased drive-hip ER ISO was associated with increased net energy outflow from the trunk to the humerus and from the humerus to the forearm. No significant effects of hip ROM or other hip ISO measures were observed. Additionally, pitchers who achieved higher peak rates of distal outflow tended to achieve higher pitch speeds. Conclusions An association was present between drive-hip ER ISO and the net energy flow out of the distal ends of the trunk and humerus during the acceleration phase of the Windmill softball pitch, emphasizing the importance of hip and lower body strength in executing the whole-body Windmill pitch. Overall, energy-flow analysis is an interesting new way to analyze pitching mechanics and will aid in furthering our understanding of performance and injury risk in Windmill softball pitching.
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effects of hip range of motion and isometric strength on energy flow during Windmill softball pitching
Journal of Athletic Training, 2021Co-Authors: Gretchen D Oliver, Kyle Wasserberger, Anne De Swart, Kenzie B Friesen, Jessica L Downs, Nicole M BordelonAbstract:Context Inadequate hip range of motion (ROM) and isometric strength (ISO) may interfere with energy flow through the kinetic chain and result in increased injury susceptibility. Objective To examine the relationship of hip ROM and ISO with energy flow through the trunk and pitching arm segments during the Windmill softball pitch in youth athletes. A subsequent purpose was to examine the relationship between energy flow and pitch speed. Design Descriptive laboratory study. Setting University research laboratory. Participants A sample of 29 youth softball pitchers (11.2±1.3 yrs.; 155.0±10.4 cm; 53.2±12.6 kg). Main outcome measure(s) Bilateral hip internal rotation (IR) and external rotation (ER) ROM and ISO were measured. Net energy outflow and peak rates of energy outflow from the distal ends of the trunk, humerus, and forearm were calculated for the acceleration phase of the Windmill softball pitch, and pitch speed was measured. Results Regression analysis revealed a significant effect of drive hip ER ISO on the net energy flow out of the distal ends of the trunk (p=0.045) and humerus (p=0.002). Specifically, increased drive hip ER ISO was associated with increased net energy outflow from the trunk to the humerus and from the humerus to the forearm. No significant effects of hip ROM or other hip ISO measures were observed. Additionally, pitchers who achieved higher peak rates of distal outflow tended to also achieve higher pitch speeds. Conclusions There is an association between drive hip ER ISO and the net energy flow out of the distal ends of the trunk and humerus during the acceleration phase of the Windmill softball pitch, emphasizing the importance of hip and lower body strength in the execution of the whole-body Windmill pitch. Overall, energy flow analysis is an interesting new way to analyze pitching mechanics and will aid in further understanding of performance and injury risk in Windmill softball pitching.
Vladislav Akhmatov - One of the best experts on this subject based on the ideXlab platform.
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modelling and transient stability of large wind farms
International Journal of Electrical Power & Energy Systems, 2003Co-Authors: Vladislav Akhmatov, Hans Knudsen, Arne Hejde Nielsen, Jorgen Kaas Pedersen, Niels Kjolstad PoulsenAbstract:The paper is dealing with modelling and short-term voltage stability considerations of large wind farms. A physical model of a large offshore wind farm consisting of a large number of Windmills is implemented in the dynamic simulation tool PSS/E. Each Windmill in the wind farm is represented by a physical model of grid-connected Windmills. The Windmill generators are conventional induction generators and the wind farm is ac-connected to the power system. Improvements of short-term voltage stability in case of failure events in the external power system are treated with use of conventional generator technology. This subject is treated as a parameter study with respect to the Windmill electrical and mechanical parameters and with use of control strategies within the conventional generator technology. Stability improvements on the wind farm side of the connection point lead to significant reduction of dynamic reactive compensation demands. In case of blade angle control applied at failure events, dynamic reactive compensation is not necessary for maintaining the voltage stability.
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advanced simulation of Windmills in the electric power supply
International Journal of Electrical Power & Energy Systems, 2000Co-Authors: Vladislav Akhmatov, Hans Knudsen, Arne Hejde NielsenAbstract:An advanced model of a grid-connected Windmill is set up where the Windmill is a complex electro-mechanical system. The Windmill model is implemented as a standardised component in the dynamic simulation tool, PSS/E, which makes it possible to investigate dynamic behaviour of grid-connected Windmills as a part of realistic electrical grid models. This means an arbitrary number of wind farms or single Windmills within an arbitrary network configuration. The Windmill model may be applied to the study of electric power system stability and of power quality as well. It is found that a grid-connected Windmill operates as a low-pass filter, whereby the two following observations are made: (1) interaction between the electrical grid and the mechanical systems of grid-connected Windmills is given by a low frequency oscillation as the result of disturbances in the electric grid; (2) flicker, which is commonly explained by the dynamic wind variation, may also be caused by mechanical eigenswings in the Windmill mechanical construction.
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advanced simulation of Windmills in the electric power supply
International Journal of Electrical Power & Energy Systems, 2000Co-Authors: Vladislav Akhmatov, Hans Knudsen, Arne Hejde NielsenAbstract:An advanced model of a grid-connected Windmill is set up where the Windmill is a complex electro-mechanical system. The Windmill model is implemented as a standardised component in the dynamic simulation tool, PSS/E, which makes it possible to investigate dynamic behaviour of grid-connected Windmills as a part of realistic electrical grid models. This means an arbitrary number of wind farms or single Windmills within an arbitrary network configuration. The Windmill model may be applied to the study of electric power system stability and of power quality as well. It is found that a grid-connected Windmill operates as a low-pass filter, whereby the two following observations are made: (1) interaction between the electrical grid and the mechanical systems of grid-connected Windmills is given by a low frequency oscillation as the result of disturbances in the electric grid; (2) flicker, which is commonly explained by the dynamic wind variation, may also be caused by mechanical eigenswings in the Windmill mechanical construction.
Tomonobu Senjyu - One of the best experts on this subject based on the ideXlab platform.
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sensor less maximum power point tracking control for wind generation system with squirrel cage induction generator
Renewable Energy, 2009Co-Authors: Tomonobu Senjyu, Naomitsu Urasaki, Yasutaka Ochi, Yasuaki Kikunaga, Motoki Tokudome, Atsushi Yona, Endusa Billy Muhando, Toshihisa FunabashiAbstract:This paper proposes a technique that determines the optimal Windmill operation speed and the optimal rotor flux. Moreover, the position and speed sensor-less wind generation system using the electromotive voltage observer to estimate rotor position and full-order observer to estimate rotor speed and the Windmill output torque are proposed. The position and speed sensor-less maximum power point of wind power generation system is controlled by using the above estimated values, optimized Windmill operation speed for maximum output power and optimized rotor flux for minimum generator losses. The effectiveness of the position and speed sensor-less maximum power point tracking control for wind power generation system with squirrel cage induction generator is verified by simulations. The simulation results confirm that the proposed method can estimate the operation speed efficiently.
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output power leveling of wind turbine generator for all operating regions by pitch angle control
IEEE Transactions on Energy Conversion, 2006Co-Authors: Tomonobu Senjyu, Ryosei Sakamoto, Naomitsu Urasaki, Toshihisa Funabashi, H Fujita, Hideomi SekineAbstract:Wind energy is not constant and Windmill output is proportional to the cube of wind speed, which causes the generated power of wind turbine generators (WTGs) to fluctuate. In order to reduce fluctuation, different methods are available to control the pitch angle of blades of Windmill. In a previous work, we proposed the pitch angle control using minimum variance control, and output power leveling was achieved. However, it is a controlled output power for only rated wind speed region. This paper presents a control strategy based on average wind speed and standard deviation of wind speed and pitch angle control using a generalized predictive control in all operating regions for a WTG. The simulation results by using actual detailed model for wind power system show the effectiveness of the proposed method.
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output power leveling of wind turbine generator for all operating regions by pitch angle control
IEEE Power Engineering Society General Meeting 2005, 2005Co-Authors: Ryosei Sakamoto, Tomonobu Senjyu, Naomitsu Urasaki, Toshihisa Funabashi, H Fujita, T Kinjo, Hideomi SekineAbstract:Effective utilization of renewable energies such as wind energy is expected instead of the fossil fuel. Wind energy is not constant and Windmill output is proportional to the cube of wind speed, which cause the generated power of wind turbine generators to fluctuate. In order to reduce fluctuating components, there is a method to control pitch angle of blades of Windmill. We have proposed the pitch angle control using minimum variance control in a previous work. However, it is a controlled output power for only rated wind speed region. This paper presents a control strategy based on average wind speed and standard deviation of wind speed, and pitch angle control using a generalized predictive control in all operating regions for wind turbine generator. The simulation results with using actual detailed model for wind power system show effectiveness of the proposed method.
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output power leveling of wind turbine generator by pitch angle control using adaptive control method
IEEE International Conference on Power System Technology, 2004Co-Authors: Ryosei Sakamoto, Tomonobu Senjyu, Naomitsu Urasaki, T Kinjo, Toshihisa FunabashiAbstract:Effective utilization of renewable energies such as wind energy is expected instead of fossil fuels. Wind energy is not constant and Windmill output is proportional to the cube of wind speed, which cause the generated power of wind turbine generators (WTGs) to fluctuate. In order to reduce fluctuating components, there is a method to control pitch angle of the blades of the Windmill. In this paper, output power leveling of wind turbine generator by pitch angle control using an adaptive control is proposed. A self-tuning regulator (STR) is used as the adaptive control. The control input is determined by the minimum variance control (MVC). It is possible to compensate the influence of parameter variations by using the proposed controller. The simulation results with the actual model for the wind power system show effectiveness of the proposed controller.
