Global Journal of Technology and Optimization

This paper presents an intelligent reactive power and voltage control system that has been developed over three years in Korea. The general structure and more importantly the least cost search method for a feasible solution are discussed herein. As a result, the system has shown a promising performance and will therefore be tested on Jeju Island, Korea as a part of the smart grid demonstration system.

Load frequency control in power systems introduces as one of the most important items in order to supply reliable electric power with good quality. The goals of the Load Frequency Control (LFC) are to maintain zero steady state errors in a two area interconnected power system. To achieve this goal a fast controller with having no steady-state error will be necessary to be included in power systems. In this paper a new genetic algorithm based method is presented to obtain optimal gains of this controller included in two-area interconnected power system. Simulation results in comparison with correspondence methods confirm the efficiency of proposed method through fastdamping steady-state deviations in power and frequency with presence of step load disturbance.

Constrained Optimal Power Flow (SCOPF) from 1960’s to till date. Diverse schemes and approaches on Single Area/Multi-area, algorithms, Contingency Selection, Steady and Dynamic SCOPF, Artificial Intelligence based SCOPF, Real time and SCOPF using Parallel/Distributed Processing, Economic Dispatch with Security Constraints, Decentralized SCOPF, Voltage Constrained SCOPF (VSCOPF), Incorporation of FACTS on SCOPF studies and Literatures on Applications of SCOPFetc are appraised in structured manner chronologically with detailed reviews on the strategies and the test systems used for the analysis are reported. A brief summary of the existing stratagems and test system data which can be retrieved are given in the conclusion for easy access of researchers

The ultimate goal of this paper is to control the angular speed ω , in a model of a DC motor driving an inertial load has the angular speed, ω , as the output and applied voltage, app v , as the input, by varying the applied voltage using different control strategies for comparison purpose. The comparison is made between the proportional controller, integral controller, proportional and integral controller, phase lag compensator, derivative controller, lead integral compensator, lead lag compensator, PID controller and the linear quadratic tracker design based on the optimal control theory. It has been realized that the design based on the linear quadratic tracker will give the best steady state and transient system behavior, mainly because, the other compensator designs are mostly based on trial and error while the linear quadratic tracker design is based on the optimal control theory which can give best dynamic performance for the controlled system.

The importance of effective energy conversion control, including power generation from renewable and environment-friendly energy sources, has increased due to rising energy demand. Power electronic systems for controlling and converting electrical energy have become the workhorse of modern society in many applications, both in industry and in the home. Power electronics plays a very important role in traction and can be considered as workhorse of robotics and automated manufacturing systems. Power semiconductor devices are the key electronic components used in power electronic systems. Advances in power semiconductor technology have improved the efficiency, size, weight and cost of power electronic systems. At present, IGCTs, IGBTs, and MOSFETs represent modern switching devices. Power integrated circuits (PIC) have been developed for the use of power converters for portable, automotive and aerospace applications. New materials (SiC and GaN) have been introduced for advanced applications. This paper reviews the state of these devices and elaborates on their potentials in terms of higher voltages, higher power density, and better switching performance.

This paper presents a methodology development and the results achieved in the process of establishing energy management system in the City of Kragujevac (Serbia) and in its public services. The paper is an overview of influential factors in the field of energy management, analyzing their impact on raising the energy efficiency of individual utility service and the city of Kragujevac, as a whole. The paper also presents the most interesting scientific and research projects realized in the cooperation of several actors which were coordinated by Regional Euro Energy Efficiency Center Kragujevac. The municipal companies together with the city administration are the direct beneficiaries of the results realized in the following areas:

‐ Development of energy management in municipalities and the establishment of energy planning at the local level;

‐ Improvement of municipal services by applying energy efficiency measures in public enterprises:

‐ “Energetika” (heating),

‐ “Cistoca” (communal waste management),

‐ “Vodovod i kanalizacija” (water and waste water management);

Promotion of ideas and projects realized in the field of energy management, environmental protection and sustainable development at the Festival of energy efficiency (starting from this year) held during the April.

The annual global clear sky illuminance available at points on the earth between the Arctic and Antarctic circles, at various altitudes is presented as an upper bound to available global illuminance. The analysis is based on measurements of illuminance obtained using a spectroradiometer. A simplified expression which may be used to predict the illuminance within 2% of the integrated results is presented. It is suggested that the effects of cloud cover may be included by using data readily available from NASA.

The recent decades have seen the increase in demand for reliable and clean form of electricity derived from renewable energy sources. One such example is solar power. The challenge remains to maximize the capture of the rays from the sun for conversion into electricity. This paper presents the steps of implementing a dual-axis solar tracking controller. This is done so that rays from the sun fall perpendicularly unto the solar panels to maximize the capture of the rays by pointing the solar panels towards the sun and following its path across the sky. Thus electricity and efficiency increased.

In this paper, a general-purpose fuzzy controlled charger for a set of Ni-Cd batteries is investigated, Simulated and experimentally tested. The fuzzy controller applied to a BUCK converter as a battery charging system and during the charge process, battery temperature and voltage variations are used as controller input variables and charge current as output .Battery voltage and temperature is kept safe and stable during the charge process. Experimental results also confirmed by computer simulation and show control potentialities

In this paper, we present a method for designing a passive optical based single-hop wavelength division multiplexing multicast network architecture that can achieve a scalable structure and form the basis of a wavelength efficient single-hop WDM network. The proposed architecture minimizes the number of wavelengths required for efficient multicast service and also minimizes tunability requirement of the transceivers. The network size scalability is achieved by adding transmitters and receivers to the designated groups. We show that the proposed system can accommodate large tuning delays and keeps with suitable throughput when the number of wavelength is equal to the number of nodes. We also show that the design can lead to a scalable structure while minimizing the number of wavelengths and tunability of the transceivers required for an efficient multicast service resulting in an improved system throughput and delay performance

Because of leading the environmental disasters, the global climate alteration has been one of the most important controversial issues in decades. The greenhouse gas emissions (CO2, methane, nitric oxide, ozone etc.) begin with the industrial revolution. After this milestone, the global warming is getting worst as long as the energy demands are met by the fossil fuels. There are a lot of factors to evaluate the performance of the supply chains such as customer service, quality, lead time, cost etc. But due to the environmental requirements (social responsibilities, Kyoto Protocol, government agencies etc.) an increasing attention has to be given to develop environmental strategies. If the aforementioned environmental applications are considered in the supply chains, then we called Green Supply Chain (GrSC). This study develops a model of a closed-loop supply chain network which starts with the suppliers and recycles with the decomposition centers. As a traditional network design, we consider minimizing the all transportation costs and the raw material purchasing costs. To pay attention for the green impacts, different transportation choices are presented between echelons according to their CO2 emissions. The plants can purchase different raw materials in respect of their recyclable ratios. The focuses of this paper are conducting the minimizing total CO2 emissions. Also we try to encourage the customers to use recyclable materials as an environmental performance viewpoint besides minimizing total costs. A multi objective linear programming model is developed via presenting a numerical example. We close the paper with recommendations for future researches.

The gear is a major mechanical element for the power transmission between two adjacent axes. Even though tooth profile of the gear is made of involute and cycloid curve, involute curved gear is generally used by the easiness of the fabrication and assembly. There are lots of studies for the gear design but mostly weighted toward to the drawing production and two dimensional modeling. And because the exclusive three dimensional gear design program is costly high, it is only used at the very confined fields. In this study, we developed automatic gear design program to create three dimensional model and gear profile of the spur and helical gear with involute tooth profile by using user development program named Visual LISP on the AutoCAD and compared each gear tooth profile which is created by automatic design program and commercial program named KissSoft, Inventor utilizing exclusive reverse engineering program named RapidForm XOV and performed gear fabrication through wire cutting electric discharge machining and after that, we compared gear measured data which was made by three dimensional scanner and made by the fabricated gear to check accuracy of the gear profiles. And also checked interference and undercut of the gear tooth by using gear driving motor.

Heat pipe is device working on two phase change of working fluid inside. This phase change of working fluid lead to increasing heat transport efficiency of heat pipe. The basic heat pipe working position is vertical position, when the heat pipe can transport maximal heat flow from evaporator to condensator. This article deal about wick heat pipe construction and propose device to identify thermal performance. The result of article is comparison of thermal performance transported by heat pipe from working positions