Three Phase Four Wire Shunt Active Filter Based on p-q theory

This Active filter based on the p-q theory is effectively compensating the harmonic currents.

Here, three-phase four wire source is implemented with phase to phase voltage of 400 v. It consists of Swing type generator. Unbalanced and Non-Linear Load is constructed using three bridge rectifiers connected to each phase and Neutral. Construction of Non-Linear load comprises only resistive and Inductive Load connected to the Bridge rectifier.
A block called Shunt Active Filter is compensating the harmonic currents, Neutral current and reactive currents. This block is connected at the PCC through the circuit breaker. This block calculates the Instantaneous active and reactive power of Non-Linear load based on Instantaneous P-Q theory . Thus obtained Active Power is filtered. Filtered Instantaneous Active Power together with Ploss, Reactive Power and neutral current are transformed to current in αβ frame. Thus obtained currents in αβ undergo inverse Clarke transformation and reference currents are calculated. Now, According to the reference current hysteresis band controller generates signals to Inverter. And these currents are feed to the load. This block is consists of following components
a. Clarke transformation blocks
b. P-Q calculation block
c. Digital High pass filter
d. A αβ calculation block
e. Inverse Clarke transformation block
f. Capacitors and Digital PI controller (Ploss calculation)
g. Three phase Inverter
h. Hysteresis band controller