The Experts below are selected from a list of 39645 Experts worldwide ranked by ideXlab platform
Fuesang Lien - One of the best experts on this subject based on the ideXlab platform.
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pitch angle control for a small scale darrieus vertical axis wind turbine with straight blades h type vawt
Renewable Energy, 2017Co-Authors: Gebreel Abdalrahman, William Melek, Fuesang LienAbstract:Abstract Unlike horizontal axis wind turbines (HAWTs), the Darrieus vertical axis wind turbine (H-type VAWT) has been the subject of only a few recent studies directed at improving its self-starting capability and/or aerodynamic performance. The technique currently used for improving the performance of this type of turbine is pitch angle control. This paper presents intelligent blade pitch control for enhancing the performance of H-type VAWTs with respect to power output. To determine the optimum pitch angles, ANSYS Fluent Computational Fluid Dynamics (CFD) software was used for a study of the aerodynamic performance of a 2D variable pitch angle H-type VAWT at a variety of tip speed ratios (TSRs). For each case examined, the power coefficient ( C p ) was calculated and compared to published experimental and CFD findings. The results obtained from the CFD model were then applied for the construction of an aerodynamic model of an H-type VAWT rotor, which constituted a prerequisite for designing an intelligent pitch angle Controller using a multilayer perceptron artificial neural network (MLP-ANN) method. The performance of the MLP-ANN blade pitch Controller was compared to that of a Conventional Controller (PID). The findings demonstrate that for an H-type VAWT, compared to a Conventional PID Controller, an MLP-ANN results in superior power output.
Alireza Bakhshai - One of the best experts on this subject based on the ideXlab platform.
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A new control approach based on the differential flatness theory for an AC/DC converter used in electric vehicles
IEEE Transactions on Power Electronics, 2012Co-Authors: Majid Pahlevaninezhad, Pritam Das, Josef Drobnik, Praveen K. Jain, Alireza BakhshaiAbstract:AC/DC converters used for charging high-voltage battery banks in electric vehicles from the utility mains, generally, consist of two stages. The first is a power factor correction (PFC) ac/dc boost converter to reduce the input current harmonics injected to the utility grid and convert input ac voltage to an intermediate dc voltage (dc-bus voltage). The second part is an isolated dc/dc converter for providing high-frequency galvanic isolation. This paper presents a novel intelligent control law based on the differential flatness theory to control the input power of the PFC stage which is determined by the charging characteristics of the high-energy battery bank, instead of controlling the intermediate dc-bus voltage at a constant value as done in the Conventional Controller. Application of the proposed control law to such an ac/dc converter helps improve the dynamic behavior of the input PFC stage compared to the Conventional Controller and also achieve load adaptive regulation of the intermediate dc-bus voltage. Such load-adaptive dc-bus voltage regulation allows the dc/dc full-bridge converter to operate optimally from no-load to full-load conditions unlike the Conventional Controller with constant dc-bus voltage which forces the dc/dc full-bridge to operate with very low duty ratios at no-load conditions. Experimental results from a 3-kW ac/dc converter are presented in the paper to validate the proposed control method. The improved converter performance and increased efficiency as compared to the Conventional control method proves the superiority of the proposed technique.
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A Nonlinear Optimal Control Approach Based on the Control-Lyapunov Function for an AC/DC Converter Used in Electric Vehicles
IEEE Transactions on Industrial Informatics, 2012Co-Authors: Majid Pahlevaninezhad, Pritam Das, Josef Drobnik, Praveen K. Jain, Gerry Moschopoulos, Alireza BakhshaiAbstract:AC/DC converters used in electric vehicles generally consist of two stages: an input power factor correction (PFC) boost AC/DC stage that converts input AC voltage to an intermediate DC voltage and reduces input current harmonics injected to the grid, and a DC/DC converter that provides high-frequency galvanic isolation. Since there is a low-frequency ripple (second harmonic of the input ac line frequency) in the output voltage of the PFC AC/DC boost converter, the voltage loop in the Conventional control system typically has a very low bandwidth to avoid distorting the input current waveform. This causes the Conventional PFC Controller to have slow dynamics against load variations. This paper presents a new control approach that regulates the input power of the converter instead of the output voltage by using an optimal nonlinear control approach based on the Control-Lyapunov Function (CFL). In this paper, it is shown that the proposed Controller is able to eliminate the low bandwidth voltage control loop in the Conventional PFC Controller, thus allowing the front-end AC/DC boost PFC converter to operate with faster dynamic response than with the Conventional Controller approach. Experimental results from a 3 kW AC/DC converter are presented in the paper to validate the proposed control method and its superior performance.
K R Sudha - One of the best experts on this subject based on the ideXlab platform.
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fuzzy c means clustering for robust decentralized load frequency control of interconnected power system with generation rate constraint
International Journal of Electrical Power & Energy Systems, 2012Co-Authors: K R Sudha, Butchi Y Raju, Chandra A SekharAbstract:Abstract Load–frequency control (LFC) is important in electric power system design and operation moreover, to ensure the quality of the power supply. Literature shows that Fuzzy logic Controller, one of the most useful approaches, for utilizing expert knowledge, is adaptive in nature and is applied successfully for power system stabilization control. Fuzzy Controller’s design depends mainly on the rule base and membership functions over the Controller’s input and output ranges. The simple and efficient clustering algorithms permit the classification of the data in distinct groups using distance and/or similarity functions. The present paper proposes the generation of optimal Fuzzy rule base by Fuzzy C-Means clustering technique (FCM) for load frequency control. The phase-plane plot of the inputs of the Fuzzy Controller is utilized to obtain the rule-base in the linguistic form. The system parametric uncertainties are obtained by changing parameters by 40% simultaneously from their typical values. The performance of the proposed FCM Controller is compared with Conventional Controller and original Fuzzy Controller in the presence of Generation Rate Constraint (GRC) in case of two area and three area inter connected power systems.
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robust decentralized load frequency control of interconnected power system with generation rate constraint using type 2 fuzzy approach
International Journal of Electrical Power & Energy Systems, 2011Co-Authors: K R Sudha, Vijaya R SanthiAbstract:Abstract The Load Frequency Control (LFC) problem has been a major subject in electrical power system design/operation. LFC is becoming more significant recently with increasing size, changing structure and complexity in interconnected power systems. In practice LFC systems use simple Proportional Integral (PI) Controllers. As the PI control parameters are usually tuned, based on classical approaches. Moreover, they have fixed gains; hence are incapable of obtaining good dynamic performance for a wide range of operating conditions and various load changes, in multi-area power system. Literature shows that fuzzy logic Controller, one of the most useful approaches, for utilizing expert knowledge, is adaptive in nature and is applied successfully for power system stabilization control. This paper proposes a Type-2 (T2) fuzzy approach for load frequency control of two-area interconnected reheat thermal power system with the consideration of Generation Rate Constraint (GRC). The performance of the Type-2 (T2) Controller is compared with Conventional Controller and Type-1 (T1) fuzzy Controller with regard to Generation Rate Constraint (GRC). The system parametric uncertainties are verified by changing parameters by 40% simultaneously from their typical values.
Gebreel Abdalrahman - One of the best experts on this subject based on the ideXlab platform.
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pitch angle control for a small scale darrieus vertical axis wind turbine with straight blades h type vawt
Renewable Energy, 2017Co-Authors: Gebreel Abdalrahman, William Melek, Fuesang LienAbstract:Abstract Unlike horizontal axis wind turbines (HAWTs), the Darrieus vertical axis wind turbine (H-type VAWT) has been the subject of only a few recent studies directed at improving its self-starting capability and/or aerodynamic performance. The technique currently used for improving the performance of this type of turbine is pitch angle control. This paper presents intelligent blade pitch control for enhancing the performance of H-type VAWTs with respect to power output. To determine the optimum pitch angles, ANSYS Fluent Computational Fluid Dynamics (CFD) software was used for a study of the aerodynamic performance of a 2D variable pitch angle H-type VAWT at a variety of tip speed ratios (TSRs). For each case examined, the power coefficient ( C p ) was calculated and compared to published experimental and CFD findings. The results obtained from the CFD model were then applied for the construction of an aerodynamic model of an H-type VAWT rotor, which constituted a prerequisite for designing an intelligent pitch angle Controller using a multilayer perceptron artificial neural network (MLP-ANN) method. The performance of the MLP-ANN blade pitch Controller was compared to that of a Conventional Controller (PID). The findings demonstrate that for an H-type VAWT, compared to a Conventional PID Controller, an MLP-ANN results in superior power output.
Chandra A Sekhar - One of the best experts on this subject based on the ideXlab platform.
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fuzzy c means clustering for robust decentralized load frequency control of interconnected power system with generation rate constraint
International Journal of Electrical Power & Energy Systems, 2012Co-Authors: K R Sudha, Butchi Y Raju, Chandra A SekharAbstract:Abstract Load–frequency control (LFC) is important in electric power system design and operation moreover, to ensure the quality of the power supply. Literature shows that Fuzzy logic Controller, one of the most useful approaches, for utilizing expert knowledge, is adaptive in nature and is applied successfully for power system stabilization control. Fuzzy Controller’s design depends mainly on the rule base and membership functions over the Controller’s input and output ranges. The simple and efficient clustering algorithms permit the classification of the data in distinct groups using distance and/or similarity functions. The present paper proposes the generation of optimal Fuzzy rule base by Fuzzy C-Means clustering technique (FCM) for load frequency control. The phase-plane plot of the inputs of the Fuzzy Controller is utilized to obtain the rule-base in the linguistic form. The system parametric uncertainties are obtained by changing parameters by 40% simultaneously from their typical values. The performance of the proposed FCM Controller is compared with Conventional Controller and original Fuzzy Controller in the presence of Generation Rate Constraint (GRC) in case of two area and three area inter connected power systems.