A novel approach to multiple dominant current harmonics removal under realistic utility condition of harmonic unbalance

The present work aims to remove dominant current harmonics (5
^th
,7
^th
,11
^th
and 13
^th
) of a 240V(rms) utility at the point of common coupling for the harmonically unbalanced condition of source current, using parallel combination of two shunt hybrid active filters. The harmonically unbalanced condition of source current has been created by connecting different types of non-linear loads in different phases of the three phase supply i.e. three phase diode bridge rectifier in abc, single phase fully controlled bridge rectifier in phase a & b and single phase ac voltage controller in phase b & c. Due to the different types of non-linear loads connected in the different phases, there are unequal magnitudes of harmonics in different phases thus leading to the harmonic unbalance in the source current. Fourier analysis is used for detection of the desired harmonic from the load current and Sinusoidal Pulse Width Modulation technique has been used to produce gating pulses for the active filter.