A novel approach to determine reference compensation currents
of the three-phase shunt active power filter (APF) under distorted and/or imbalanced source voltages .
Compensation currents in a-AY axis are computed according to equation (6).
LPF are used in feed forward configuration to obtain harmonic compensation currents.
Inverse Park transform is used to obtain compensation current reference.
Compensation current is calculated from the non-linear load current (Ia Ib Ic) and source voltages (Va, Vb,Vc).
The biggest difference value in of both compensation currents is around [+ or -]7 A (Fig.
is the load current and iC is the compensation current then
In comparison of the obtained compensation current with that, which is obtained according to p-q theory, maximum variation in current is [+ or -] 7 A.
To calculate the reference compensation currents in the a-p coordinates, the expression 3 is inverted as given below,
In order to obtain the reference compensation currents in the a-b-c coordinates the inverse of the transformation is applied to eqn 2 and is given as
The performance of an active filter depends mainly on the technique used to compute the reference current and the control method used to inject the compensation current in to the line .
The performance of the active filter mainly depends on the technique used to compute the reference current and the control strategy followed to inject the desired compensation current into the line.