Comparison of three evolutionary algorithms for harmonic mitigation using SAPF

For power quality improvement, shunt active power filters (SAPF) having PWM controlled voltage source inverter (VSI) topology is extensively used in distribution networks, which utilizes the PI controller for reference voltage tracking. PI controller tuning with the assumption of linear PWM model leads to unsatisfactory results under varying operating conditions. Optimal tuning of PI gains is required to get the best response of PI controllers. This paper presents a comparative study of PI controller tuning in a SAPF using three evolutionary algorithms (EAs), viz. bacteria foraging (BF), bacteria foraging with swarming (BFS) and particle swarm optimisation (PSO), for current harmonic mitigation. The minimization of integral time square error (ITSE) and integral time absolute error (ITAE) as performance indices is used as objective function for optimisation. The simulation results show that PSO tuned PI with ITSE as minimized parameter performs better.