The proposed controller (FPPC) was implemented using fuzzy membership functions, the phase plane theory and the IA. Fig. 1 shows the block diagram for controlling the speed
of an induction motor using the IFOC. The proposed FPPC has one output (U(n) , the torque
T and two input state variables (the state E(n) and the variation of the error state dE
(n)). Substituting (11) and (12) into (13) yields the output U(n) shown as (21).