A FUZZY CONTROLLER FOR GENERATOR EXCITATION CONTROL

A new approach based on fuzzy set theory is proposed for the design of an excitation controller for a synchronous generator. In the proposed fuzzy expert system, generator speed deviation (DELTAomega) and acceleration (DELTAomega) are taken as controller inputs. These input signals are first characterized by linguistiC Variables using fuzzy set notations. A fuzzy relation matrix is built to give the relationship between controller input and controller output. A set of fuzzy logic operations are performed by the fuzzy excitation controller using controller inputs and fuzzy relation matrix to get the desired controller output. To demonstrate the effectiveness of the fuzzy excitation controller, digital simulations of a power system subject to a three-phase fault under different operating conditions are performed. It is found that the fuzzy excitation controller can improve the dynamic performance of a power system over a wide range of operating conditions. Since the fuzzy excitation controller does not require model identification, it can be easily implementated on a microcomputer.