A new fuzzy logic-based controller design method for DC and AC impressed-voltage drives

This paper deals with the design of fuzzy logic-based controllers (FLBC) fo r de and ac electric drives. Industrial drives employ the cascaded PI contr ol with a subordinated current control loop to make sure that the current d oes not exceed the admissible value and improve dynamic performances. The n onlinear FLBC characteristics permit one to achieve the performances of the cascaded control using only one control loop. This is feasible by a suitab le choice of the scaling factors together with the rules of the fuzzy contr oller. The Authors propose a minimum number of rules and the criteria, base d on physical considerations, to determine the input and output gains inste ad of using the trial and error procedure. The designed FLBC is able to con trol the speed of a de drive as well as the rotor speed and flux of a vecto r-controlled induction motor drive. Computer simulations show the effective ness of the new fuzzy-controller design method. The reduced number of rules and membership functions and the application flexibility together with the possible implementation on low cost mu Ps let us think the proposed tuning criteria will be widely adopted.