Loading...
Search for:
turbines
0.008 seconds
Total 588 records
Optimization of operating parameters in a hybrid wind-hydrogen system using energy and exergy analysis: Modeling and case study
, Article Energy Conversion and Management ; Volume 106 , December , 2015 , Pages 1318-1326 ; 01968904 (ISSN) ; Ahmadi, S ; Mirghaed, M. R ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
In this study, hybrid renewable energy system based on wind/electrolyzer/PEM fuel cell are conceptually modeled, and also, exergy and energy analysis are performed. The energy and exergy flows are investigated by the proposed model for Khaf region-Iran with high average wind speed and monsoon. Exergy and energy analysis framework is made based on thermodynamic, electro-chemical and mechanical model of the different component of hybrid system. Also, the effects of various operating parameters in exergy efficiency are calculated. The results show an optimum wind speed where the exergy efficiency and power coefficient is at maximum level, and also, when the ambient temperature start to be...
Stochastic Reconfiguration and Optimal Coordination of V2G Plug-in Electric Vehicles Considering Correlated Wind Power Generation
, Article IEEE Transactions on Sustainable Energy ; Volume 6, Issue 3 , 2015 , Pages 822-830 ; 19493029 (ISSN) ; Niknam, T ; Fotuhi Firuzabad, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
This paper investigates the optimal operation of distribution feeder reconfiguration (DFR) strategy in the smart grids with high penetration of plug-in electric vehicles (PEVs) and correlated wind power generation. The increased utilization of PEVs in the system with stochastic volatile behavior along with the high penetration of renewable power sources such as wind turbines (WTs) can create new challenges in the system that will affect the DFR strategy greatly. In order to reach the most efficiency from the PEVs, the idea of vehicle-to-grid (V2G) is employed in this paper to make a bidirectional power flow (either charging/discharging or idle mode) strategy when providing the main charging...
Alternative biomass fuels consideration exergy and power analysis for hybrid system includes PSOFC and GT integration
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 37, Issue 18 , Sep , 2015 , Pages 1962-1970 ; 15567036 (ISSN) ; Ghadamian, H ; Roshandel, R ; Moghadasi, M ; Sharif University of Technology
Taylor and Francis Inc
2015
Abstract
The present study aims to analyze a combined heat and power (CHP) system with an approach towards exergy analysis and employing biomass gasification. The cycle modeling was carried out using Cycle-Tempo and the main purpose was to achieve parametric analysis of the model. The systems function was studied by categorizing alternative biomass fuels, also qualitative and quantitative analyses of the biomass fuel samples were presented and considering the trade-off points, most appropriate biomass fuel with respect to exergy efficiency and delivered power were determined. The results indicated that the bagasse and wood chips had the total exergy efficiency of 54.5 and 57.1% in trade-off point,...
A control scheme to enhance low voltage ride-through of brushless doubly-fed induction generators
, Article Wind Energy ; November , 2015 ; 10954244 (ISSN) ; Oraee, H ; Zolghadri, M. R ; Rahimi, M ; Sharif University of Technology
John Wiley and Sons Ltd
2015
Abstract
The use of brushless doubly-fed induction generator has been recently proposed for wind turbines because of its variable speed operation with fractional size converter without the need to brush and slip ring. This paper introduces a control scheme to improve low voltage ride-through capability of doubly-fed induction generator considering grid code requirements. The proposed control strategy is based on analysis of flux linkages and back electromotive forces and intends to retain the control-winding current below the safety limit (typically 2pu) during severe voltage dips. The time-domain simulations validate effectiveness of the proposed scheme to protect the converter against failure as...
Buckling analysis of tapered composite beams using a higher order finite element formulation
, Article Journal of Reinforced Plastics and Composites ; Volume 29, Issue 17 , 2010 , Pages 2663-2683 ; 07316844 (ISSN) ; Ganesan, R ; Sharif University of Technology
2010
Abstract
Tapered composite beams are increasingly being used in various engineering applications such as helicopter yoke, robot arms, and turbine blades. In the present work, the buckling analysis of laminated tapered composite beams is conducted using a higher order finite element formulation. In tapered laminates, the material and geometric discontinuities at ply drop-off locations lead to significant discontinuities in stress distributions. Higher order formulation ensures the continuity of the stress distribution through the thickness of a laminate as well as across the element interfaces, which is very important for the analysis of tapered laminates. In addition, higher order finite element...
Efficient control scheme of wind turbines with doubly fed induction generators for low-voltage ride-through capability enhancement
, Article IET Renewable Power Generation ; Volume 4, Issue 3 , May , 2010 , Pages 242-252 ; 17521416 (ISSN) ; Parniani, M ; Sharif University of Technology
2010
Abstract
As the penetration of wind power in electrical power systems increases, it is required that wind turbines remain connected to the grid and actively contribute to the system stability during and after grid faults. This study proposes an efficient control strategy to improve the low-voltage ride-through (LVRT) capability in doubly fed induction generators (DFIGs). The proposed scheme consists of passive and active LVRT compensators. The passive compensator is based on a new crowbar arrangement located in series with stator windings. It considerably reduces the rotor inrush current at the instants of occurring and clearing the fault. The active LVRT compensator is realised through rotor voltage...
Determination of the extended Drucker-Prager parameters using the surrogate-based optimization method for polypropylene nanocomposites
, Article Journal of Strain Analysis for Engineering Design ; Volume 51, Issue 3 , 2016 , Pages 220-232 ; 03093247 (ISSN) ; Majzoobi, G. H ; Bagheri, R ; Sharif University of Technology
SAGE Publications Ltd
2016
Abstract
In this article, a new method is proposed to identify the constants of the extended Drucker-Prager yield surface for polypropylene nanocomposites. The method is based on optimizing the difference between the numerical and the experimental results of a three-point bending test. The test specimens are made of polypropylene/nanoclay and polypropylene/nano-calcium carbonate nanocomposites with different nanoparticles content. Moreover, the effect of composite filler content on the extended Drucker-Prager constants of polypropylene, as the composite matrix, is investigated. Inasmuch as numerical simulation is usually very time-consuming and highly nonlinear, a surrogate-based model with radial...
A control scheme to enhance low voltage ride-through of brushless doubly-fed induction generators
, Article Wind Energy ; Volume 19, Issue 9 , 2016 , Pages 1699-1712 ; 10954244 (ISSN) ; Oraee, H ; Zolghadri, M. R ; Rahimi, M ; Sharif University of Technology
John Wiley and Sons Ltd
Abstract
The use of brushless doubly-fed induction generator has been recently proposed for wind turbines because of its variable speed operation with fractional size converter without the need to brush and slip ring. This paper introduces a control scheme to improve low voltage ride-through capability of doubly-fed induction generator considering grid code requirements. The proposed control strategy is based on analysis of flux linkages and back electromotive forces and intends to retain the control-winding current below the safety limit (typically 2 pu) during severe voltage dips. The time-domain simulations validate effectiveness of the proposed scheme to protect the converter against failure as...
Three-phase PFC rectifier with high efficiency and low cost for small PM synchronous wind generators
, Article 7th Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2016, 16 February 2016 through 18 February 2016 ; 2016 , Pages 302-307 ; 9781509003754 (ISBN) ; Tahami, F ; Valipour, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Small Permanent Magnet Synchronous Generators (PMSG's) are widely used in low power wind turbines. In order to inject the electrical power, generated by PMSG, to the grid, a back-To-back AC/AC power electronic converter is required. In this paper, a novel low cost efficient AC/DC converter is proposed for rectifier stage to obtain the maximum power per ampere of PMSG by using Power Factor Correction method. The new structure is based on DCM SEPIC converter. Reducing the number of semi-conductor switches has decreased converter cost. Additionally, other advantages of this Converter are employing easy control method to obtain the maximum power per ampere and using Synchronous inductance of...
Improving the performance of a nonlinear boiler–turbine unit via bifurcation control of external disturbances: a comparison between sliding mode and feedback linearization control approaches
, Article Nonlinear Dynamics ; Volume 85, Issue 1 , 2016 , Pages 229-243 ; 0924090X (ISSN) ; Abbasi, M. H ; Moradian, H ; Sharif University of Technology
Springer Netherlands
Abstract
Boiler–turbine units may show quasiperiodic behavior due to the bifurcation occurrence in the presence of harmonic disturbances. In this study, a multi-input–multi-output nonlinear dynamic model of a boiler–turbine unit is considered. Drum pressure, electric output, and fluid density are the state variables and adjusted at the desired values by manipulation of the input variables. Control inputs are the valve positions for fuel, steam and feed-water flow rates. To improve the quasiperiodic behavior of the system and bifurcation control in tracking problem, two controllers are designed: feedback linearization control and nonlinear sliding mode control (SMC). The feedback linearization...
Modeling and control of zero-sequence circulating current in parallel converters with space vector modulation
, Article IEEE Journal of Emerging and Selected Topics in Power Electronics ; Volume 5, Issue 1 , 2017 , Pages 363-377 ; 21686777 (ISSN) ; Amouzegar Ashtiani, N ; Parniani, M ; Mokhtari, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
The use of parallel converters is one of the most practical solutions to solve the problem of transmitting bulk power generated in megawatt wind turbines to the grid. In spite of several advantages of paralleling, some considerations must be taken into account. Zero-sequence circulating current flowing between parallel converters is one of these concerns. Characteristic differences and discrepancy of zero-axis duty cycles of the parallel converters are considered as the main origins of this current. This paper investigates another source of this phenomenon in space vector modulation controlled converters. This unnoticed source is the notable third-harmonic voltage generated in the...
Experimental works on dynamic behavior of laminated composite beam incorporated with magneto-rheological fluid under random excitation
, Article ACM International Conference Proceeding Series, 8 February 2017 through 12 February 2017 ; Volume Part F128050 , 2017 , Pages 156-161 ; 9781450352802 (ISBN) ; Zabihollah, A ; Behzad, M ; Sharif University of Technology
Association for Computing Machinery
2017
Abstract
Laminated composite structures are widely being used in modern industries particularly robot arms, aerospace and wind turbine blades where the structures mainly exposed to harsh random vibration and in turn, leads to unpredicted failure. Adding Magneto-rheological (MR) fluids in such structures may significantly improve their dynamic response. In the present work, the vibration response of laminated composite beams filled with MR fluids (MR laminated beam) under random loading has been investigated using experimental as well as simulation approaches. Finite Element Model (FEM) has been utilized to simulate the vibration response under random loading. An in-house set-up has been designed to...
Influence of interfacial adhesion on the damage tolerance of Al6061/SiCp laminated composites
, Article Ceramics International ; Volume 43, Issue 2 , 2017 , Pages 2632-2643 ; 02728842 (ISSN) ; Pouraliakbar, H ; Jandaghi, M. R ; Bagheri, R ; Seyed Reihani, S. M ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
In this study, lamination as extrinsic mechanism was considered to enhance damage tolerance of three-layer Al6061-5%vol. SiCp/Al1050/Al6061-5%vol. SiCp composites. To fabricate laminates of dissimilar interfacial adhesion, different rolling strains were applied during hot roll-bonding. The discrepancy in interfacial strength of laminates was examined by shear test while toughness values were studied using three-point bending test. It was revealed that both interfacial adhesion and damage tolerance were influenced by rolling strain. Interfacial bonding played the major role in the energy absorption during fracture which was quantified as initiation, propagation and total toughness. The...
Multilevel optimization of the splitter blade profile in the impeller of a centrifugal compressor
, Article Scientia Iranica ; Volume 24, Issue 2 , 2017 , Pages 707-714 ; 10263098 (ISSN) ; Hajilouy Benisi, A ; Durali, M ; Sharif University of Technology
Sharif University of Technology
2017
Abstract
In this research, multi-level optimization of the profile of the splitter blades of a turbocharger compressor is performed using genetic algorithm in order to improve its performance. Successive corrections of the profile at hub, mid-span, and shroud of the splitter blades, with the objective of decreasing the incidence losses at the leading edge and adjustment of the blade loading at the shroud, result in an impeller having improved splitter blades. The impeller flow field analysis shows that the optimization has been successful in reducing the flow leakage at the shroud region as well as the losses in the leading edge region. Although numerical simulations predict a decrease by 0.5% in...
Profit-based unit commitment of integrated CHP-thermal-heat only units in energy and spinning reserve markets with considerations for environmental CO2 emission cost and valve-point effects
, Article Energy ; Volume 133 , 2017 , Pages 621-635 ; 03605442 (ISSN) ; Ardehali, M. M ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
For the purposes of lowering environmental emission cost and increasing economic profit, energy efficient combined heat and power (CHP) units can be integrated with conventional separate heat and power production units to meet heat and power demands. The goal of this study is to develop and examine a novel heuristic and deterministic optimization algorithm for solving the profit-based unit commitment (PBUC) problem for a generation company with integrated CHP-thermal-heat only system for (i) satisfying demands for heat and power, (ii) selling spinning reserve for power, (iii) reducing environmental CO2 emission cost, and (iv) accounting for valve-point effects for steam turbines. For...
A novel FRT strategy based on an analytical approach for PMSG-based wind turbines with ESS power rating reduction
, Article Turkish Journal of Electrical Engineering and Computer Sciences ; Volume 26, Issue 5 , 2018 , Pages 2737-2752 ; 13000632 (ISSN) ; Ajami, A ; Mokhtari, H ; Hojabri, H ; Sharif University of Technology
Abstract
In this paper an analytical approach is proposed to formulate the proper set of phase currents reference to ride the permanent magnet synchronous generator (PMSG)-based wind turbine (WT) through faults properly, regardless of fault type. Hence, the WT is forced to inject required reactive current by grid codes together with active power injection, to help support grid frequency during faults and reduce the energy storage system (ESS) power rating. Moreover, it prevents pulsating active power injection to the grid. During grid faults, the DC-link voltage is controlled by the ESS instead of the grid-side converter (GSC) and the GSC controller applies calculated reference currents. The ESS...
Lifetime optimization framework for a hybrid renewable energy system based on receding horizon optimization
, Article Energy ; Volume 150 , 1 May , 2018 , Pages 617-630 ; 03605442 (ISSN) ; Roshandel, R ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this work, a novel convex sequence framework for real-time receding horizon operation optimization of a hybrid renewable energy system integrated with optimal sizing is presented to increase the penetration rate of renewable energy in supplying the demand. The proposed framework optimizes the entire lifetime cost of a system consisting of two main steps which are 1) design & installation and 2) operation as two sequence modules. This framework is applied to a hybrid renewable energy system which includes PV, wind turbine, batteries and a diesel generator. In the operation optimization, receding horizon strategy is used to optimize the operation schedule. Mixed integer convex programming...
Using Web-GIS technology as a smart tool for resiliency management to monitor wind farms performances (Ganjeh site, Iran)
, Article International Journal of Environmental Science and Technology ; 2018 ; 17351472 (ISSN) ; Abbaspour, M ; Radfar, R ; Mohammadi, A ; Sharif University of Technology
Center for Environmental and Energy Research and Studies
2018
Abstract
Considering the wide spread locations of wind farms in Iran, it is important to develop a suitable decision support system (DSS) to fulfill proper management of wind farms. Extensive literature survey indicates that there are no integrated forms of DSS to manage a set of wind farms. The existing wind farms are performing independently, and there is no practical method for exchanging the online data. DSS can contribute to optimal operation of wind farms, operation and maintenance scheduling, pricing policy, etc. In this study, a geographic information system and RETSCREEN software were linked to the designed DSS to achieve a more suitable result. Also, a huge number of data are constantly...
Assessing the effect of wind farm layout on energy storage requirement for power fluctuation mitigation
, Article IEEE Transactions on Sustainable Energy ; 15 May , 2018 ; 19493029 (ISSN) ; Oraee, H ; Pal, B. C ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Optimization of wind farm (WF) layout has been studied in the literature with the objective of maximizing the wind energy capture. Based on the power spectrum density (PSD) theorem, this paper shows that the WF layout affects not only the total harvested energy but also the level of power fluctuation, which in turn influences required capacity of battery energy storage system (BESS) needed to mitigate the inherent power fluctuation of the wind farms. Since both harvested energy level and BESS capacity directly influence the profit of WF owner, the effect of WF layout on these quantities are taken into account simultaneously and WF layout optimization problem is redefined. Genetic algorithm...
A comprehensive thermo-economic analysis, optimization and ranking of different microturbine plate-fin recuperators designs employing similar and dissimilar fins on hot and cold sides with NSGA-II algorithm and DEA model
, Article Applied Thermal Engineering ; Volume 130 , February , 2018 , Pages 1090-1104 ; 13594311 (ISSN) ; Sadeghi, S ; Khanjarpanah, H ; Haghshenas Gorgani, H ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
This study aims to perform a comprehensive thermo-economic analysis, optimization and ranking of cross and counter-flow plate-fin recuperators employing rectangular, triangular, offset strip and louver fins. The analysis is mainly conducted for two recuperator structures: (i) fins’ configurations on both hot and cold sides are the same; (ii) fins on hot side and cold side are dissimilar in configuration. Considering effective practical optimization constraints and design parameters, Non-dominated Sorting Genetic Algorithm (NSGA-II) is used to maximize the recuperator effectiveness and minimize its total cost, simultaneously. Pareto-optimal fronts are presented to specify the desirable...