Comparison of fuzzy logic based dc voltage control strategies for a three phase parallel active filter

This paper is on the performance compazison of vazious PI type Fuzzy Logic Controllers for a three phase, three-wired Pazallel Active Filter (PAF) system, consisting of an Insulated Gate Bipolar Transistor (IGBT) based current controlled PWM Voltage Source Inverter. As a novelty in PAF applications, a Self Tuning Fuzzy Logic Controller is developed in order to improve the dynamic behavior of the system. The performance of the self tuning fuzzy control is compared with that of two Mamdani type fuzzy PI controllers with symmetric and asymmetric triangulaz membership functions, as well a classical linear PI controller. Simulations aze performed to evaluate the system performance in terms of maximum overshoot (T_m), rise time (t_r), and settling time (t_s) of the do capacitor voltage to the 2% of the reference do voltage. The results show that the self tuning fuzzy control improves the dynamic behavior of the PAF, while maintaining the improved Total Harmonic Distortion in the ac source current (THDi_as) and the near unity power factor operation provided by the other methods. The obtained results also demonstrate the advantage of the proposed scheme as an efficient gain adaptation mechanism in comparison to standard fuzzy PI schemes, for systems that are subject to frequent and sudden load changes.