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

摘要

This paper deals with the design of fuzzy logic-based controllersn(FLBC) for DC and AC electric drives. Industrial drives employ thencascaded PI control with a subordinated current control loop to makensure that the current does not exceed the admissible value and improvendynamic performances. The nonlinear FLBC characteristics permit one tonachieve the performances of the cascaded control using only one controlnloop. This is feasible by a suitable choice of the scaling factorsntogether with the rules of the fuzzy controller. The authors propose anminimum number of rules and the criteria, based on physicalnconsiderations, to determine the input and output gains instead of usingnthe trial and error procedure. The designed FLBC is able to control thenspeed of a DC drive as well as the rotor speed and flux of anvector-controlled induction motor drive. Computer simulations show theneffectiveness of the new fuzzy-controller design method. The reducednnumber of rules and membership functions and the application flexibilityntogether with the possible implementation on low cost ΜPs lead thenauthors to think that the proposed tuning criteria will be widelynadopted