Modelling and Control of Active Power Filter

Abstract

The advancement in technology from the last few decades demand the use of power electronics- newlinebased equipment s not only on the load end but also in transmission and generating stations for newlineswitching and controlling applications. The proliferation of these power electronics devices newlinewith nonlinear load like adjustable speed drives, electronic ballasts and arc welder distorts the newlinesource current profile and induce various power quality issues in the system. Various issues that newlinearise at PCC (point of common coupling) are harmonics, fluctuations, glitches, sag/dip, swell newlinesurges, spikes, notches, flickering etc. The inefficiency of conventional equipment s for newlineharmonic mitigation led to use of passive filters. It is combination of passive element inductor newlineand capacitor. Using these passive elements, passive filter can be used for various filtering newlineapplication. Passive filters have their own challenges of parallel resonance with network newlineimpedance, fixed compensation, large size and over compensation of reactive power at newlinefundamental frequency. The increased severity of harmonic pollution, attracts the attention of newlinesystem engineer to provide dynamic and adjustable compensation to power quality issues. newlineActive power filter that are popularly known as active line conditioner fulfil the requirement of newlinesystem engineers to provide complete solution to the issues like voltage and current harmonics, newlinecompensation of reactive power, terminal voltage regulation, voltage balance in all phase and newlinesuppression of flickers. newlineThe active power filter has two broad categories, that are series active power filter and shunt newlineactive power filter, effectiveness of the filter depends on the control technique implemented and newlinethe semiconductor technologies used. Voltage source inverter (VSI) based approach is newlineimplemented in shunt APF. A large number of control algorithms are presented in literature, newlinewhich are broadly put in two category names as time domain and frequency domain. newline