Optimization of PI Controller Gains in Nonlinear Controller of STATCOM Using PSO and GA

Abstract

According to nonlinear operation of

STATCOM, nonlinear controller has a better

performance in comparison with linear controller.

Regulating the DC capacitor voltage in STATCOM is a

common task and can improve the system dynamic. The

nonlinear control is based on exact linearization via

feedback. A PI controller exists in this control system to

regulate the capacitor voltage. In conventional scheme,

the trial and error method has been used to determine

PI controller coefficients. In this paper, the effect of PI

gains on responses of Vdc, Id and Modulation Index (M)

is presented. The exact calculation of optimized PI

coefficients can be carried out to reduce disturbances

and steady state error in DC link voltage. Therefore, in

this paper, Particle Swarm Optimization (PSO)

approach is used. It is shown that capacitor voltage

tracks the reference value and vibrations are less than

conventional status. Also, Genetic Algorithm (GA) has

been used and compared with the results.