Improved load frequency control of power system using LMI based PID approach

In this paper an approach for designing an optimum gain of Proportional integral derivative (PID) controller subject to Linear matrix inequality (LMI) constraints for load frequency regulation of single area and multi-area power system is presented. The LMI based PID control reduces the required control effort while assuring that pre-defined design conditions for dynamic response of system like settling time, overshoot and Integral square error. Further a subset of complex plane with respect to the design conditions is mapped onto a stability region in the coefficient space of the characteristic polynomial. Next, the stability region in the polynomial coefficient space defines LMI as a constraint, which is used to find the optimum gain of PID controllers. A series of simulations results are performed for efficacy of proposed design approach especially for dynamic response of single area and multi-area power system which is superior in comparison to other design method obtained from literature. The simulation results demonstrate that the designed controller can effectively restrain the impact of variation in system parameters and load disturbance.