Mohsen Atash Ab-Parvar; Hamed Hekmati; Alireza Siadatan; Mehdi Bigdeli; Arsalan Hekmati; Mehdi Bagheri
Abstract
Wind power as a renewable energy has the potential to become a clean energy source in almost all countries of the world but, there are lots of technical challenges that need to be addressed in advance. Wind speed variation (WSV) is one of the most important issues. Separate from its mechanical effects ...
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Wind power as a renewable energy has the potential to become a clean energy source in almost all countries of the world but, there are lots of technical challenges that need to be addressed in advance. Wind speed variation (WSV) is one of the most important issues. Separate from its mechanical effects on wind turbines (WTs), it causes electrical power variations on WT as well. Doubly Fed Induction Generators (DFIGs) and Maximum Power Point Tracking (MPPT) system have been helpful so far but some problems such as inertia still needed to be solved. Inertia in the WTs causes a delay on MPPT. This paper proposes a novel method to increase WTs output power in which a DFIG equipped with an energy storage system such as Ultra-capacitor helps MPPT system to track the wind variations rapidly by absorption or injection energy during the wind changes. The ultra-capacitor and control system are modeled and simulated in Matlab/Simulink® environment. The simulation results proofs that the proposed system can improve electrical power and increase electrical energy during WSVs. The simulation model will lead to more penetration of wind power and also enables engineers to optimize the system.
Hamed Hekmati; Mohammad Siamaki; Arsalan Hekmati
Abstract
As a technology, superconductivity has had a great contribution to the advancement of medical science, electronics, astronomy and transportation. With the improvements in the field of superconductivity, the discovery of new materials with better properties, commercialization of these materials, and regarding ...
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As a technology, superconductivity has had a great contribution to the advancement of medical science, electronics, astronomy and transportation. With the improvements in the field of superconductivity, the discovery of new materials with better properties, commercialization of these materials, and regarding the importance of rotary equipment in major industry, trends in research and development of superconducting magnetic bearings is broadened day by day. High efficiency compared to the cost of manufacturing and maintenance of these bearings as well as the increasing need to economic save in key industry, could reinforce the tendency to use these bearings instead of conventional bearings. Superconducting magnetic bearings have various structures, all of which can be used for various applications. In recent decades efforts have been made to design new structures for specific applications. In this paper a general review of magnetic bearings’ history as well as their existing structures is investigated and the theoretical and experimental results have been presented for a studied bearing system.
