Figure 8: Block diagram of controller 2
The firstly the values of induction motor output are applied to
fuzzy logic controller1 and duty ratio is found out which is
applied on the VSI output and then to the induction motor and
current values of the induction motor output are found out and
checked whether the stator flux lies in the same sector of VSI
or not.[9]If the sector has changed then the fuzzy logic
controller 2 is applied and change in duty ratio is found out
and again applied to induction motor and same controller is
used till flux lies in same sector and if sector changes the fuzzy
logic controller 1 is applied.
The output of fuzzy logic controller is added to the previous
value of duty ratio and then applied to the motor.
Basis of formation of rules
The two inputs are divided into groups of proper intervals and
also similarly the output.
Previous value of torque- T1
Current value of torque- T2
Reference torque-T
Previous torque error- (T-T1)
Torque increment-(T2-T1)
Therefore by selecting any value of reference torque, T
according to groups divided, the value of T1 and T2 would be
able to find the related group of output depending upon the
groups in which the input lies and hence the rules can be
formed.