Power Quality Improvement Using Self-tuning Pi Controlled Statcom by Particle Swarm Optimization

In recent years, there has been an increasing interest on applying advanced and intelligent control designs in power engineering area. As a heuristic optimization technique, Particle Swarm Optimization (PSO) is used for tuning the parameters of the STATCOM. 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 project, the effect of PI gains on responses of Vdc , Idc 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. An efficient formula for the estimation of system load impedance using real-time measurements is derived. Based on the estimated system load, a PSO algorithm, which takes the best particle gains, the best global gains, and previous change of gains into account, is employed to reach the desired controller gains. To demonstrate the effectiveness of the proposed PSO self-tuning PI controller for a STATCOM, experimental results for a system under different loading conditions are presented. Results from the self-tuning PI controller are compared with those from the fixed-gain PI controllers. KeywordsSTATCOM, FACTS, self-tuning PI controller, Particle swarm optimization, Voltage Source Converter MATLAB / SIMULINK