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Browsing by Author "Hamzehlouia, Sina"
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Item ENERGY STORAGE SYSTEM FOR HYDRAULIC WIND ENERGY TRANSFERS(Office of the Vice Chancellor for Research, 2012-04-13) Hamzehlouia, Sina; Izadian, AfshinGearless hydraulic transmissions are considered noble candidates for wind power transfer systems. Hydraulic wind power transfer systems allow collecting the energy of multiple wind turbines into one generation unit. Fur-thermore, elimination of the gearbox as a bulky and expensive to maintain component reduces the cost of energy conversion. The hydraulically con-nected harvesting systems require controllers to maintain the frequency and generate the required power. However, the intermittent nature of wind im-poses fluctuation on the amount of generated wind power and on the fre-quency of the output voltage. This poster introduces a wind energy storage technique through a hydraulically connected wind power transfer system. The simulation results demonstrate the successful operation of the storage to maintain the fluid in the system to keep the generator speed at a prede-termined value. The system is mathematically modeled and the control sys-tem is derived.Item MODELING AND CONTROL OF HYDRAULIC WIND ENERGY TRANSFERS(2012-05) Hamzehlouia, Sina; Izadian, Afshin; Anwar, Sohel; Wasfy, TamerThe harvested energy of wind can be transferred to the generators either through a gearbox or through an intermediate medium such as hydraulic fluids. In this method, high-pressure hydraulic fluids are utilized to collect the energy of single or multiple wind turbines and transfer it to a central generation unit. In this unit, the mechanical energy of the hydraulic fluid is transformed into electric energy. The prime mover of hydraulic energy transfer unit, the wind turbine, experiences the intermittent characteristics of wind. This energy variation imposes fluctuations on generator outputs and drifts their angular velocity from desired frequencies. Nonlinearities exist in hydraulic wind power transfer and are originated from discrete elements such as check valves, proportional and directional valves, and leakage factors of hydraulic pumps and motors. A thorough understanding of hydraulic wind energy transfer system requires mathematical expression of the system. This can also be used to analyze, design, and predict the behavior of large-scale hydraulic-interconnected wind power plants. This thesis introduces the mathematical modeling and controls of the hydraulic wind energy transfer system. The obtained models of hydraulic energy transfer system are experimentally validated with the results from a prototype. This research is classified into three categories. 1) A complete mathematical model of the hydraulic energy transfer system is illustrated in both ordinary differential equations and state-space representation. 2) An experimental prototype of the energy transfer system is built and used to study the behavior of the system in different operating configurations, and 3) Controllers are designed to address the problems associated with the wind speed fluctuation and reference angular velocity tracking. The mathematical models of hydraulic energy transfer system are also validated with the simulation results from a SimHydraulics Toolbox of MATLAB/Simulink®. The models are also compared with the experimental data from the system prototype. The models provided in this thesis do consider the improved assessment of the hydraulic system operation and efficiency analysis for industrial level wind power application.