Energy Sytems Enginerring

In this study, a fuzzy logic controller, based on state space modelling of dc-dc converter, for a separately excited dc traction motor is developed to improve the speed control system for which relevant heuristic knowledge of system dynamics is available. Rule base of fuzzy controller is defined by the understanding of the behaviour of the system. The use of fuzzy logic may enable designers to improve system performance without having to develop system mathematical models. The state space averaging method has been applied successively to model the dynamic characteristics of the switching converter.

In this investigation, a virtual classroom for Uşak University's Electricity Program is designed, implemented and then tested by using the 3D virtual environment Second Life. When online, learners and instructors are able to correspond with each other by using their own avatars, chat vocally, make presentations and watch videos, as well as utilise all opportunities of a 3D virtual environment. Furthermore, learners can access the educational materials of the Electricity Program and interact with each other even when the educator is not available, giving opportunities for both synchronous and asynchronous distance education. The 3D virtual environment is analysed and evaluated here in terms of education costs, and advantages or disadvantages for both learner and educator.

The purpose of tunnel ventilation control is to provide a safe and comfortable environment for users. The tunnel ventilation is opfimi7ed by conU'ollin~ jet falls and dust collectors iastalled inside the tunnel. The jet fans blow polluted air from iaside the tunnel toward air exit ports. Sinc,¢ this is a process involving many elements which are difficult to quantify exactly, in this paper predictive fuzzy control was introduced to solve this problem. By in(xeducing predictive fuzzy control it was made possible to greatly reduce electric power consumption while keeping the degree of pollulion within the allowable limit.

This paper presents a novel risk assessment model considering human factor based on the fuzzy logic approach. For the contribution of the literature, not only the number of people is included in the process of risk assessment, but also with the human factor as a quantitative entry in this study. A flexible and user-friendly risk assessment interface is developed using LabVIEW program, which puts at disposal different applications for the course material. Designed interface gives an opportunity to users to assess risks in a wide range of consequences containing many different combinations and options. The interface is tested for a 100-kV high-voltage cell as a case study. As a result, it is seen that the interface assesses plenty of input elements and possibilities in a short time. For this reason, the fuzzy logic approach is suggested as a suitable method for risk assessment.

The purpose of tunnel ventilation control is to provide a safe and comfortable environment for the users. The tunnel ventilation is optimized by controlling jet fans and dust collectors installed inside the tunnel. The jet fans blow polluted air from inside the tunnel toward air exit ports. The dust collectors remove soot and smoke so that pollutant concentration inside the tunnel is measured by CO (carbon monoxide) meters. Since this is a process involving many elements which are difficult to quantify exactly, in this paper predictive fuzzy control was introduced to solve this problem. By introducing predictive fuzzy control it was made possible to greatly reduce electric power consumption while keeping the degree of pollution within the allowable limit.

Absiracf-This paper introduces a fuzzy controller of the rectifier side in high voltage direct current (HVDC) system. ifier side of the typical point-to-point system has ideration.. In the rectifier, thyristors are used as ces that can han of problem and are very sensitive. Especially. in changing voltagd and frequency. these problems are appeared itself. Therefore. de current of the rectifier output becomes unstable. Also, device dissipation, transmission losses and effects of environments cause increasing of these problems. In this study, a fuzzy controller is designed to solve these problems. Finally. a comparative study has been performed with and without fuzzy controi.

This paper obtains a nonlinear mathematical model of PMSM, and realizes simulation of obtained model in Matlab/Simulink program. Speed control of motor model is made with Fuzzy Logic (FL) and Self Tuning FLPI (STFLPI) controllers. Controller performances are compared from the speed graphs obtained.

In this study, a new modified fuzzy-PI (MFPI) controller is designed to control a highpower Switched Reluctance Motor (SRM) modeled by means of the finite element method (FEM) for hybrid electric vehicle (HEV) applications. Finite element analysis has been carried out via the Maxwell 2D software package. The motor flux, inductance and torque characteristics obtained from the analyses have been presented. The obtained numerical analysis data was transferred to the Matlab/Simulink environment, and a non-linear dynamic SR motor model was created. The motor speed has been controlled by conventional fuzzy-PI (FPI) and new modified fuzzy-PI (MFPI) controller after designing the nonlinear model of the SRM. The controller performances are compared in terms of maximum percentage overshoot (O s), rise time (t r), steady-state error (e ss), rate of torque ripple (T d), and rate of ripple in speed (ωd). The comparisons for the SRM's different operation situations show that MFPI generally yields the better performance in terms of the rise-time, the steady-state error, and the maximum percentage overshoot criteria. In addition, the high-power SR motor simulation computation time (fuzzy computation) for the MFPI controller appears to be shorter than the value for the conventional FPI controller.

Due to environmental issues such as global warming and the greenhouse effect, there is a growing interest in renewable sources of energy. Wind energy, which is the most important of these energy sources, can potentially meet a portion of the global energy demand. Numerous studies are being conducted worldwide to determine how the maximum level of power can be obtained from wind energy. In these studies, there is a particular interest in permanent magnet synchronous generators (PMSGs). This is because PMSGs exhibit a good performance within a wide range wind speeds and can be driven directly. In this study, the maximum power point tracking (MPPT) of a PMSG has been carried out by using a prototype built in a laboratory environment. The simulation model has been realized by utilizing MATLAB/Simulink and implemented by using dSPACE. MPPT has been performed by employing such control algorithms as an artificial neural network, a look-up table, and curve fitting in order to carry out comparative performance analyses of these control algorithms. Controllers were analyzed through comparisons between their MPPT and process performance. Based on our analysis results, we were able to identify controllers that were better in terms of power tracking and process performance.

In this paper, proposed new control method of a separately excited dc traction motor using fuzzy logic. The design of a fuzzy logic controller for a dc motor drive, that produces the traction moment for light metro vehicle, is illustrated and implemented. The drive system has been simulated and results compared with those obtained by a conventional PID controller. The superior results in the drive performance which are achieved by fuzzy logic controller are provided. The proposed controller exhibits superior transient and steady-state performance compared to usual PID controllers. Rule-based fuzzy logic controller is implemented using a personal computer with a data acquisition card. The controller is implemented on a 486 PC using C++ program. Copyright© 1998 IFAC

In this paper, it is proposed a fuzzy logic controller for separately excited dc traction motor in light metro vehicle. The drive system has been simulated and results compared with those obtained by a conventional PID controller. The superior results in the drive performance which are achieved by fuzzy logic controller are provided. It has been shown to significantly improve the performance of a dc motor with non-linear characteristics. Proposed controller exhibits superior transient and steady-state performance compared to usual PID controllers. In addition, the controller is robust to variations in conduction mode nonlinearities. The effectiveness of fuzzy logic based control technique is also discussed.

In this paper, it is proposed a fuzzy logic controller for separately excited dc traction motor in light metro vehicle. The drive system has been simulated and results compared with those obtained by a conventional PID controller. The superior results in the drive performance which are achieved by fuzzy logic controller are provided. It has been shown to significantly improve the performance of a dc motor with non-linear characteristics. Proposed controller exhibits superior transient and steady-state performance compared to usual PID controllers. In addition, the controller is robust to variations in conduction mode nonlinearities. The effectiveness of fuzzy logic based control technique is also discussed.

Değişik rüzgâr türbin kavramları, dünya çapında kurulan rüzgâr enerji kapasitesinin önemli ölçüde büyümesi ve rüzgâr enerjisi teknolojilerinin hızlı gelişmesi ile artmaktadır. Günümüzde rüzgâr enerjisi, dünyanın en hızlı gelişen yenilenebilir enerji kaynağıdır. 2010 yılında dünya genelinde 39 GW rüzgâr kurulu gücü devreye girmiş, toplam kurulu güç 198 GW'a ulaşmıştır. 2010 yılında devreye alınan kapasitenin 18,9 GW'ı Çin'e aittir. Bunun sonucu olarak Çin, rüzgâr enerjisi kurulu gücünü 44,7 GW'a çıkararak bu alanda birinciliğe yükselmiştir. İkinci sıraya gerileyen ABD'nin rüzgâr enerjisi kurulu gücü 2010 sonu itibariyle 40,2 GW'tır [99]. Rüzgâr enerjisi kurulu gücünde Çin ve ABD'yi Almanya (27,2 GW) ve İspanya (20,7 GW) izlemektedir. 2010 yılında rüzgâr enerjisinden Almanya'da 37 TWh,

Widespread use of power electronic based equipments has been caused the distortion of electric power quality in power systems. Reactive power and harmonics are the most commonly electric power quality problems. Traditionally, passive filters are used to solve these problems. However, passive filters have some limitations in application such as land space, resonance and slow response. Recently, active power filters (AF) have been replaced with passive filters because of its advantages over conventional filters. In this paper, a simulation model of AF is prepared in Matlab/Simulink software. Simulation model covers reference current extraction, source and nonlinear load, coupling inductance, two-level inverter and control of inverter switches. Nonlinear load current includes 5 th and 7 th harmonics and AF is controlled to eliminate these harmonics. Gate pulses for inverter are generated by hysteresis control method. Fourier, instantaneous reactive power and synchronous reference frame methods are separately used to estimate reference signals. Some simulation results showing dynamic performance of AF for each extraction methods are given.