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Issue Info: 
  • Year: 

    2022
  • Volume: 

    11
  • Issue: 

    1
  • Pages: 

    27-34
Measures: 
  • Citations: 

    0
  • Views: 

    33
  • Downloads: 

    0
Keywords: 
Abstract: 

A common method for Controlling a group of parallel converters in decentralized Control strategy structure in an island microgrid, the use is the droop-down characteristics of frequency ω-P and voltage E-Q. However, the problem with using this method is that the reactive power is not properly distributed (in proportion to the capacity of the micronutrients) between the micronutrients, which may lead to overload in the converters. Microgrids may also suffer from dynamic stability problems such as power fluctuations, which can be increased by switching between active and reactive power Control. To avoid this problem, the X / R ratio of transmission lines is an important parameter that should be carefully considered in the design of micronutrient Controllers. By linearizing and simplifying conditions, the Control system conversion function model becomes a single input-single output system, which is efficient enough to show the relationship between Control parameters such as slope of droop characteristics and derivative sentences, virtual impedance, and voltage Controllers. Using this model, stability conditions for different parameters are analyzed. Also, to improve power distribution stability, common droop strategies are modified by adjusting the slope as well as adding nonlinear sentence sections. This approach reduces the coupling between active and reactive power Control and reduces the dependence of power distribution on grid parameters such as the X / R ratio. To evaluate the reliability of the proposed model, the simulation results in a sample island microgrid in MATLAB software are presented.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2022
  • Volume: 

    52
  • Issue: 

    1
  • Pages: 

    51-60
Measures: 
  • Citations: 

    0
  • Views: 

    135
  • Downloads: 

    36
Abstract: 

Non-cooperative intelligent Control agents (ICAs) with dedicated cost functions, can lead the system to poor performance and in some cases, closed-loop instability. A robust solution to this challenge is to place the ICAs at the feedback Nash equilibrium point (FNEP) of the differential game between them. This paper introduces the designation of a robust decentralized infinite horizon LQR Control system based on the FNEP for a linear time-invariant system. For this purpose, two Control strategies are defined. The first one is a centralized infinite horizon LQR (CIHLQR) problem (i.e. a supervisory problem), and the second one is a decentralized Control problem (i.e. an infinite horizon linear-quadratic differential game). Then, while examining the optimal solution of each of the above strategies on the performance of the other, the necessary and sufficient conditions for the equivalence of the two problems are presented. In the absence of the conditions, by using the least-squares error criterion, an approximated CIHLQR Controller is presented. It is shown that the theorems could be extended from a two-agent Control system to a multi-agent system. Finally, the results are evaluated using the simulation results of a Two-Area non-reheat power system.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    1386
  • Volume: 

    1
Measures: 
  • Views: 

    1982
  • Downloads: 

    0
Abstract: 

سازمان بین المللی استاندارد از زمان تاسیس خود در سال 1942، استانداردهای بین المللی متعددی را با همکار ی متخصصان و کارشناسان برجسته جهان و همچنین کارشناسان موسسه های استاندارد کشورهای عضو این سازمان، تدوین و منتشر نموده است. هر کدام از استانداردهای انتشار یافته حیطه خاصی از عملیات و فعالیتها را پوشش داده و بر روی آن متمرکز می شود. مانند استانداردهای سیستم کیفیت، ایمنی و بهداشت حرفه ای و مدیریت محیط زیست. با وجود تشابه فراوان بین این سیستم ها، ادغام نیازمندیهای این سه سیستم بدون پیچیدگی به نظر می رسد؛ ولی این امر در عمل به سادگی میسر نیست. چرا که بایستی ابتدا برای هر سازمان فایده ها، مشکلات و مسایل حاشیه ای جهت ادغام در نظر گرفته شود. علاوه بر این، در نظر داشتن وجوه اشتراک و تفاو تها بین سیستم های مورد نظر نیز ضروری است. با این حال اگر نیازمندیهای سیستم مدیریتی مورد نظر به درستی در سازمان طرح ریزی و اجرا شده باشد و کارکنان سازمان نیز آگاهی و تعهد لازم را در ارتباط با نیازمندیهای آن داشته باشند، ادغام سیستم های مدیریتی به راحتی و بدون ایجاد اختلال در روند جاری فعالیتهای سازمان امکان پذیر خواهد بود. در این مقاله پس از بحث و توضیح پیرامون استانداردهای کیفیت، مدیریت محیط زیست و ایمنی و بهداشت حرفه ای، روشهای ادغام این سه سیستم و فواید ناشی از این ادغام عنوان خواهد شد.

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Writer: 

رضائی مهدی

Issue Info: 
  • Year: 

    1394
  • Volume: 

    1
Measures: 
  • Views: 

    347
  • Downloads: 

    0
Abstract: 

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Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 347

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Issue Info: 
  • Year: 

    2024
  • Volume: 

    13
  • Issue: 

    25
  • Pages: 

    33-49
Measures: 
  • Citations: 

    0
  • Views: 

    16
  • Downloads: 

    0
Abstract: 

This article investigates the problem of simultaneous attitude and vibration Control of a flexible spacecraft to perform high precision attitude maneuvers and reduce vibrations caused by the flexible panel excitations in the presence of external disturbances, system uncertainties, and actuator faults. Adaptive integral sliding mode Control is used in conjunction with an attitude actuator fault iterative learning observer (based on sliding mode) to develop an active fault tolerant algorithm considering rigid-flexible body dynamic interactions. The discontinuous structure of fault-tolerant Control led to discontinuous commands in the Control signal, resulting in chattering. This issue was resolved by introducing an adaptive rule for the sliding surface. Furthermore, the utilization of the sign function in the iterative learning observer for estimating actuator faults has not only enhanced its robustness to external disturbances through a straightforward design, but has also led to a decrease in computing workload. The strain rate feedback Control algorithm has been employed with the use of piezoelectric sensor/actuator patches to minimize residual vibrations caused by rigid-flexible body dynamic interactions and the effect of attitude actuator faults. Lyapunov's law ensures finite-time overall system stability even with fully coupled rigid-flexible nonlinear dynamics. Numerical simulations demonstrate the performance and advantages of the proposed system compared to other conventional approaches.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    0
  • Volume: 

    1
  • Issue: 

    1
  • Pages: 

    47-47
Measures: 
  • Citations: 

    1
  • Views: 

    221
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    1394
  • Volume: 

    5
Measures: 
  • Views: 

    839
  • Downloads: 

    0
Abstract: 

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Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 839

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Writer: 

Issue Info: 
  • End Date: 

    1395
Measures: 
  • Citations: 

    3
  • Views: 

    181
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Writer: 

Issue Info: 
  • End Date: 

    1395
Measures: 
  • Citations: 

    0
  • Views: 

    172
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Author(s): 

Arash Ahmad Arash" target="_blank">Ahmad Arash Ahmad Arash | Arash Ahmad

Issue Info: 
  • Year: 

    2022
  • Volume: 

    1
  • Issue: 

    68
  • Pages: 

    295-312
Measures: 
  • Citations: 

    0
  • Views: 

    84
  • Downloads: 

    0
Abstract: 

This study explores the motivational components within teacher rating systems and their impact on professional growth motivation. Employing a systematic review approach, it investigates texts pertaining to teacher rating systems, motivation, and professional development literature. By examining various texts and research findings on teacher motivation, factors influencing teacher ratings based on general, specialized, and professional competencies, as well as experience, are identified. Drawing parallels with Herzberg's motivational theory, this study provides recommendations to bolster teacher motivation and job satisfaction through improvements in the rating system.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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