جستجوی مقالات مرتبط با کلیدواژه « کنترل هوشمند » در نشریات گروه « فنی و مهندسی »

This paper proposes a new fuzzy control for photovoltaic static compensator (PV-STATCOM) system in order to improve voltage stability. The task of proposed system is the dynamic voltage control of a solar PV system connected to load bus in different operating modes as STATCOM and/or PV active power generation. In this strategy, in case of perturbation, the proposed fuzzy controller by detecting it and considering the severity of disturbance, when there is no or insufficient remaining capacity of the inverter to compensate the reactive power, stops the active power production of the PV solar system, and then the entire capacity of the inverter is used as a STATCOM to regulate the voltage at the load bus. Then, after fixing the problem, the system returns to the active power generation mode as before. To evaluate the performance of the proposed fuzzy controller, different modes are simulated with EMTDC/PSCAD software to prove the ability of the controller to improve the stability of the power system. The results confirm that the PV-STATCOM with the proposed controller can improve the dynamic performance of the system.

In the last decades intelligent transportation systems are considered more than ever as a feasible method to control the traffic. The intelligence of this system can greatly reduce human error in crashes. Parallel parking system, car turning and automatic intellignet car are the important systems in this area. In this paper, an important factor of accidents has been discussed to reduce damages of crashes. At first the laws of car precession have been obtained according to traffic police laws and car nonholonomic constraint. Then, multiple paths and car decision capability system have been designed to access an intelligent control system. In this research design a fuzzy decision system is a novel way to decrease the accidents. Finally car dynamic analysis and MATLAB simulation have been compared to show the usability of designed intelligent precession system. Results of this paper with reasonable error illustrate the effectiveness of proposed control system.

Rapid advances in new sciences and technologies result in high penetration of smart devices and services in daily life. In this regard, smart buildings are one of the prominent examples which have dramatically improved not only the accuracy and efficiency of buildings but also the speed of daily routines. Recently, integration of the cutting-edge technologies has been traversing from residential to the office buildings even security-based organizations. The purpose of this paper is to design an intelligent traffic control system for office buildings associated with managing energy consumption, providing additional facilities such as registering appointments and alerting system to cater a secure environment for traffic control and monitoring. The proposed system consists of multiple units which are installed in several parts of the building such as entrance, staff room, and management room. These units are connected to the central processing unit at any given moment. In the following, the tasks of each unit are discussed in details and examples of overall system performance are described. Finally, the experimental results obtained from the prototype test in a 7-room building are assessed. This article is aimed at the major goals of the Iranian Journal of Energy and disseminates scientific ideas and creativity and enhances the level of theoretical and applied knowledge in the field of energy.

In this paper, a fractional-order robust adaptive intelligent controller (FRAIC) is designed for a class of chaotic fractional order systems with uncertainty, external disturbances and unknown time-varying input time delay. The time delay is considered both constant and time varying. Due to changes in the equilibrium point, adaptive control is used to update the system's momentary information and the intelligent controller is used to estimate the uncertainties and disturbances and non-linearities of the system according to the momentary information obtained. The sliding mode control, which provides closed loop asymptotic stability in the system despite the uncertainties and disturbances, is used as a robust controller. Using the Lyapunov theorem and Barbalat's Lemma, the asymptotic stability of a chaotic fractional order system with input delay and uncertainty as well as external disturbance is proved by designed controller. Finally, using the simulation results of financial as well as supply and demand systems, the performance of designed controller would be examined.

In recent years, the distributed generation resources (DGR) have become an essential and inseparable component in power networks and have achieved major success. Improving network power voltage, helping in peak load conditions and reducing load on power lines and transformers, utilizing renewable energies and reducing environmental pollution constitute some of the reasons for their expansion. In contrast to all these advantages in a given network, the increased presence of distributed generation resources has presented new challenges for power networks. One of the most important problems is the impact on system protection functionality. The traditional protection structure of the networks will be impaired and malfunctioned due to the presence of distributed generation resources. In this paper, a new intelligent linear control algorithm is used to restore the protective coordination. The proposed method modifies the protection characteristic curve of the protection system by adjusting the overcurrent relay current coefficient. This control procedure is in accordance with the widely applied over-current relay curves and complies with the relevant standards. For this purpose, by using a new drop control block and local sampling of over-current relay current, current setting of the relay is recovered to keep the correct operation of protection system. The proposed method is evaluated on two real micro-grids test system in Isfahan province by ETAP software. The findings indicate the ability of this method in coordinating the protection functionality of micro-grids with high penetration coefficient of DGR.

Today, in order to take advantage of the systematic management of traffic flows in metropolitan areas, using intelligent transportation systems has been increasingly noticed. In this regard, one of the intelligent traffic control tools with dynamic act which plays an important role in directing and controlling traffic flow, are variable message signs. In principle, the effectiveness of the signs (like other technologies) is subject to a number of factors including font, color and etc. Changing each one of these factors will cause different reactions in drivers. Survey research conducted has shown that the best colors to display, are green, orange and amber. Furthermore, displaying a message line has a better impact on driving performance. In this study, citizen's awareness of these signs was assessed via questionnaire. Analysis of the results shows that the lack of proper information signs and sign’s authority to obligate drivers to comply with the message, were the fundamental weakness. The viewpoint of the majority of citizens indicates confidence in the "medium" and "low" compared to the information provided by the signs . On the other hand, experts views indicate the wrong location of traffic signs and their weakness in responsing the needs. Cultivation also considered necessary in order to inform drivers and radio and television have been introduced as the best tools for this purpose.

In this paper، an energy management in a building with zero energy with renewable sources، solar، fuel cell and grid- connected electric vehicle will be provided. For this purpose، mathematical models for each of these sources and power electronic converters for hybrid power generation system with regard to the time of the simulation. A prominent feature of this work can be coordinated planning electric vehicle to cover the building''s load. To validate the performance of the proposed power management strategy، simulation was performed in MATLAB software. The results show that the proposed power management enables the implementation of zero energy in the building.

In the past, the field of missile guidance and control system design has been dominated by classical control techniques. Typically these techniques are either time domain or frequency domain based, are applicable to linearized and time-invariant plants. Nonlinearities and time-varying effects must be coped with by a robustness margin of the control loop. The performance of the loop is hence not constant but will change with the operating point. When the time variation and nonlinearities are severe, it may not be an easy task to find a controller that can cope with it all. In recent years, we have seen a growing interest in applications of robust, nonlinear, adaptive and intelligent control theories to missile flight guidance and control systems. The main advantage of intelligent over classical control is that the former can provide robust systems when there are model and environmental uncertainties. Fuzzy logic, by giving control laws based on input-output relationships, avoids the need for accurate knowledge of system dynamics, and is thus insensitive to their changes. In simple systems the classical controller may be preferred while systems with more complex requirements and capabilities, the increased abilities of the fuzzy controller may be useful. In such a system, it is frequently advantageous to use hybrid intelligent systems. The resulting control system can incorporate many desirable qualities, such as robustness, ease of adaptability to new tasks, and is faster to produce than traditional methods that are heavily model dependent. Another feature of intelligent systems is that they could combine knowledge, techniques, and methodologies from various sources. These intelligent systems supposed adapt themselves and learn to enhance the performance in changing environments. In this paper, an adaptive control structure based on fuzzy logic theory is presented. In this structure the control objective is track the command of Euler angles. In the aforementioned control system, fuzzy controllers knowledge-base, rule base are updated with continuous adjustment of membership function and weight of fuzzy controller though online learning. In this approach, fuzzy systems are used to approximate unknown ideal controllers. The adjustable parameters of the fuzzy systems are updated by an adaptive law based on a Lyapunov approach, i.e., the parameter adaptive laws are designed in such a way to ensure the convergence of a Lyapunov function. Finally the Simulation results for an air to ground short range missile with uncertain aerodynamic coefficients are presented to proof the proposed control law.