The use of modern power electronic equipment has changed our lives but also changed the load characteristics of modern facilities. Electronic loads have earned the name “Non-linear load” to describe the way they draw the power. The injected harmonics, reactive power burden, unbalance and excessive neutral currents cause low system efficiency and poor power factor. Harmonic contamination has become a major concern for power system specialists due to its effects on sensitive loads and on the power distribution system. Due to the finite (non zero) internal impedance of the utility source, the voltage waveform at the point of common coupling (PCC) to other loads will be distorted, which may cause them to malfunction. Various standards and guidelines have been established that specify limits on the magnitudes of harmonic currents and harmonic voltage distortion at various harmonic frequencies. These have been achieved using filtering system, which consists of passive and active filters & control. The proposed work deals with the design of Active filters to reduce the voltage/current harmonics in power supply system connected to Power Electronic Systems. Brief reviews from literature for various conventional active harmonic filters that are used in many industrial power systems are presented. A new control algorithm for shunt active filter is designed which uses less number of sensors and less number of control loops. The proposed algorithm works in continuous conduction mode. The operation, analysis and design of various Active/Hybrid filters are detailed and verified through MATLAB simulation.
