ABSTRACT
This chapter deals with the minimisation of the problem of overshoot in transient phase and load rejection phase. Zeigler–Nichols tuned PID controller can be regarded as a popular controller among process industries. But it cannot restrict the overshoot to the satisfactory limit. Hence, fixed setpoint weighting and variable setpoint weighting provide improvement to some extent only in the transient phase. Moreover, the enhancement in both phases can be observed by applying dynamic setpoint weighting. On the other hand, it has to be remarked that the enhancement in transient phase in case of dynamic setpoint weighting is not within the satisfactory limit. So, for the further enhancement, fractional order PID (FOPID) (denoted by PIλDμ) has been improvised here. The simple design and easy tuning scheme of the parameters λ and μ have added more advantage. The superiority of the proposed scheme has been evaluated through the comparison of the performance indices along with the responses applying to the two basic models and their perturbed models.
