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RISS 인기검색어
- 검색키워드
- 저자 : Banadaki, Ali Dehghan (검색결과 2 건)
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Banadaki, Ali Dehghan ProQuest Dissertations & Theses West Virginia Univ 2022 해외박사(DDOD)
소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.
This dissertation develops and analyzes distributed controllers for power systems with renewable energy sources. A comprehensive state space modeling of voltage source inverters (VSIs) is developed specifically to address the secondary voltage control. This model can be used for simulation and control design. Unlike frequency, voltage is a local phenomenon, meaning that it cannot be controlled from a far distance. Therefore, a voltage zoning matrix that relates the sensitivity of the loads to the sources is proposed. The secondary voltage control is designed by applying the eigenvalue decomposition of the voltage zoning matrix to obtain the reference generators voltages. The developed algorithm in this study has been tested on multiple IEEE case studies, and the results show its effectiveness, yet it is a centralized control algorithm. To reduce the risk of a single point of failure in the centralized controllers, distributed secondary voltage controllers have been proposed in the recent literature. However, the communication messages are still exchanged among all controllers in the system. Therefore, a fully distributed algorithm is proposed in this dissertation study through the design of a communication layer by clustering the sources based on a developed sensitivity methodology. A modified IEEE 13 bus feeder with integrating renewable energy sources shows a significant improvement in time of convergence. A real communication protocol is then applied to the system to analyze the communication effect of packet loss and latency on the given distributed control system. Furthermore, to demonstrate the voltage control problem on the hardware-in-the-loop system, the detailed steps to implement the simulation model in the OPAL-RT real-time simulator (RTS) are discussed. The results of RTS coordinate with the software modeling outcomes.
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Dehghan Banadaki, Arash North Carolina State University 2013 해외박사(DDOD)
소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.
Predicting the ultimate performance of asphalt concrete under realistic loading conditions is the main key to developing better-performing materials, designing long-lasting pavements, and performing reliable lifecycle analysis for pavements. The fatigue performance of asphalt concrete depends on the mechanical properties of the constituent materials, namely asphalt binder and aggregate. This dependent link between performance and mechanical properties is extremely complex, and experimental techniques often are used to try to characterize the performance of hot mix asphalt. However, given the seemingly uncountable number of mixture designs and loading conditions, it is simply not economical to try to understand and characterize the material behavior solely by experimentation. It is well known that analytical and computational modeling methods can be combined with experimental techniques to reduce the costs associated with understanding and characterizing the mechanical behavior of the constituent materials. This study aims to develop a multiscale micromechanical lattice-based model to predict cracking in asphalt concrete using component material properties. The proposed algorithm, while capturing different phenomena for different scales, also minimizes the need for laboratory experiments. The developed methodology builds on a previously developed lattice model and the viscoelastic continuum damage model to link the component material properties to the mixture fatigue performance. The resulting lattice model is applied to predict the dynamic modulus mastercurves for different scales. A framework for capturing the so-called structuralization effects is introduced that significantly improves the accuracy of the modulus prediction. Furthermore, air voids are added to the model to help capture this important micromechanical feature that affects the fatigue performance of asphalt concrete as well as the modulus value. The effects of rate dependency are captured by implementing the viscoelastic fracture criterion. In the end, an efficient cyclic loading framework is developed to evaluate the damage accumulation in the material that is caused by long-sustained cyclic loads.
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