A PROPOSED APPROACH TO CONTROL OF AUTOMATIC VOLTAGE REGULATOR SYSTEM USING INTELLIGENT CONTROL TECHNIQUE

In recent years, the world has moved toward the intelligent control to obtain the optimal solution for the big problems. The main aim of this paper is to obtain the best performance for the Automatic Voltage Regulator (AVR) system by using the fuzzy logic controller tuned by genetic algorithm. The genetic algorithm approach is used here to change the scaling gains at the inputs, output of fuzzy controller, and tuning the membership function with stay the fuzzy rules without changing. The proposed approach has been tested and compared with PID controller and without controller. The simulation has been performed using C++ programming language (version 5.02) along with MATLAB program that has been used for plotting time response. 89:; ا ةABCDا تاFG ا HI ، ةAKB ا LآNO=> لF9Q>ا LRIا S9T لFUQ9> VBآW>ا ةAKB ا ةNXYNZ [>N\>ا VXYا ، H]BYN^_FYوDا V^B;>Fa>ا [bG^=> ءادا LR^Iا S^9T لFU^Q>ا F^ه f^Qg>ا h^_ H ا فk^l>ا ) AVR ( ماkQ;^noZ VBGBX>ا تNB_زراF:>NZ [GrG_ s_Nt AKB ا u_k:;nا ذإ LR^Iا دN^Xxاو A^BBrY H^I N^Gه V^BGBX> VR^_Nr>ا لاوk^ >ا ةk^TNyZ []Q;^ >ا [^ Y z>W^آو جاA^CDاو لN^CدDا تاA^ Br;=> [B^| ) fuzzy membership function ( H^K\Y H^;>او ةAKB ا k^TاF| تF^g}Zو V^BGBX>ا تNB_زراF:>NZ لk\_ s_Nt AKB مN^bG9> VZNX;nا LRIا ، F|و V^yxAK>ا ةW^ه تA^g;Cاو H^~}>ا AKB ا ^_ u^ر ) PID ( V^=xky>ا V^yxAK>او ) h^_ AKB ا Wه VX_AZو LB}=Y [Y ) C++ ( _NAZو MATLAB مNbG>ا VZNX;nا [nر HI . 2. Introduction Fuzzy Logic was initiated in 1965, by Lotfi A. Zadeh. Fuzzy systems are particularly suitable for modeling and classification problems as a human expert [1].In the past years more researches have been devoted to augment the approximate reasoning method of fuzzy systems with the learning capabilities of neural networks and evolutionary algorithms [2]. In power system studies, there are many elements affecting stability of the system. These factors need be addressed before proceeding to design any simulation program for the power system. The AVR has a substantial effect on transient stability when varying the field voltage to try to maintain the terminal voltage constant [3]. There are a number of efficient search algorithms that have their origins in the field of biological evolutionary and are known as evolutionary computation, the field of evolutionary computation is comprised mainly of Genetic Algorithms (GAs), Genetic programming (GP) and Evolutionary Strategies (ES) [4]. + Received on 5/12/2005 , Accepted on 8/2/2007 * Asst. Lecturer\ Technical Collage / Almusyeib\ Electrical Power Engineering Technique,Baghdad,Iraq. ** Asst. Lecturer\Technical Collage / Almusyeib\Electrical Power Engineering Technique ,Baghdad,Iraq. In this work, these algorithms are used to tuning the inputs and output scaling parameters and fuzzy membership function bases of the fuzzy controller to obtain the optimal rules for control system under the condition of no expert. This paper is organized as follows: after the introduction, Automatic Voltage Regulator (AVR) system is presented in section 3, a Genetic-Fuzzy Controller Design (GFC) is presented in section 4. Result of testing the proposed approach is addressed in section 4. Finally the conclusions are given. 3. Automatic Voltage Regulator System A simple automatic voltage regulator (AVR) is shown in Figure (1) First order model of synchronous generator is: