Modelling and simulation of single-phase parallel active power filters

Wide spread use of semiconductor elements in power electronics applications have yield harmonics in energy transmission lines. These harmonics cause voltage and current wave shapes to be differ from main component wave shape, reduce power factor, increase power losses and damage electrical and electronic systems. Active and passive filtration systems are used for the suppression and elimination of the harmonics induced in the mains. Traditional passive filtration systems includes inductor and capacitor can suppress harmonics for only defined range of harmonics but active filters can suppress and eliminate harmonics in the more frequency range. Today, widely used active power filters can be used in various forms such as series active power filters, parallel active power filters, combination of these two and hybrid active power filters. In this thesis, it's aimed to eliminate or suppress harmonics in single-phase source caused by the nonlinear loads using parallel active filter. A single-phase nonlinear load model has been constructed and the harmonics induced in the source caused by the nonlinear load was observed. A single-phase parallel active power filter is modelled and used for the suppression of source harmonics. The whole system is simulated using Matlab/Simulink simulation environment. The current wave shape is recorded before and after use of active power filter. The effectiveness of the active power filter is observed from the obtained results. It has been observed that the suppression of harmonics is under the value defined by international standards.