Comparative study of switching signal generation techniques for three phase four wire shunt active power filter

In this paper the performance of three switching signal generation techniques for three phase four wire shunt active power filters are compared for balanced and unbalanced load conditions. The techniques which are considered for comparative study are (i) Traditional Hysteresis Current Control Method, (ii) Three Dimensional space vector modulation with null vector, (iii) Three dimensional space vector modulation without null vector. Comparison is done using simulation studies carried out in MATLAB / SIMULINK environment. It is shown through simulation studies that switching losses in the voltage source inverter of active power filter are reduced in three dimensional space vector modulation without null vector as the number of switches controlled at any instant of time is six out of eight.