For measuring circuit experimental structures optimum value [K.sub.b] at the minimum integral square error or maximum dynamic deflection ranged from 1.5 to 4.5.

The dependence of integral square error of [K.sub.b] for different structure variants: 1--CL with SD, SHD, and in the absence of HPF at the input; 2--CL with SD, SHD in the absence of HPF at the input; 3--CL with SD, SHD and HPF on the input with w/[w.sub.S] = 15.3; 4--CL with SD and in the presence of HPF on the input with w / ]w.sub.S] = 15.3; 5--CL with SD and SHD and HPF on the input with w/[w.sub.S] = 29.4; 6--CL with SD and HPF on the input with w/[w.sub.S] = 29.4.

But it produces steady state error, oscillatory response and high

integral square error. In the proposed controller these problems have been rectified for pitch controlled variable speed wind turbine.

It is inferred that FLC controller gives less Settling time (Ts) and Integral Square Error (ISE) for both the process to reach the desired set point.

It is inferred that MPC controller gives less Settling time (Ts) and Integral Square Error (ISE) for both the process to reach the desired set point.

For Conventional PI Controller, gain [K.sub.p] & [K.sub.i] has been optimized using

Integral Square Error (ISE) criterion.

The evaluation parameters such as Rise Time, Settling Time, Integral Absolute Error (IAE),

Integral Square Error (ISE) and Integral of Time and Absolute Error(ITAE) is calculated for the above heat exchangers and their comparative results are shown in T-1.

Integral Square Error (ISE), Integral Time Square Error (ITSE) and Integral Time Absolute Error (ITAE) cost functions are used for the purpose of optimizing conventional controller gain value of the AGC system.