Abstract

The design methods of fuzzy logic controls (FLC's) based genetic algorithms (GA's) are used to get an optimized and additional control signal to the high voltage direct current (HVDC) systems, through genetic algorithms. The optimal values for the gain factors associated with each of the two fuzzy logic controller inputs and its output is achieved without changing the membership functions or the rule base of the fuzzy logic controller itself. This paper proposes the different methods of using genetic algorithms in the design of fuzzy logic controller's optimal inputs and output called genetic algorithm based fuzzy logic control. The implementation of genetic algorithms in designing an optimal PI-fuzzy logic controller for an HVDC system, applying the new proposed technique is introduced. The results of designing an optimal genetic algorithms based PI-fuzzy logic controller (GA-PI-Fuzzy) are compared with those obtained using the PI-fuzzy logic controller (PI-Fuzzy) and those obtained using genetic algorithm based fixed element control (GA-FEC). In designing the PI-fuzzy logic controller, two factors are used the scaling factor (or the normalized space of variables) and the gain factor (or the actual space of variables).

Key words: High voltage direct current (HVDC) system, power system, genetic algorithm, fuzzy logic control.