The factors Kw and Ke are chosen to normalize the speed error ∆ wn , and the change of speed error ∆en , respectively, so that these remain within the limit of ±1. Factor Ki is so chosen that one can get the rated current for rated conditions. Here, the constants are taken as
Kw =* wr (command speed), Ke=10, and Ki= 10 in order to get the optimum drive performances. After selecting the scaling factors, the next step is to choose the membership
function of , and wrn en∆ ∆*qn i , which perform the important task of the the fuzzy-logic controller The membership functions used for the input and output fuzzy sets are shown in Fig.2.