A novel control strategy based shunt APLC for power quality improvements

This paper presents shunt active power line conditioners for power quality improvement such as harmonics and reactive power compensation due to non-linear loads. The novel compensation control strategy is based on positive sequence voltage detector with generalized Fryze currents minimization, an approach different from conventional methods; the purpose is to guarantee linearity between the supply voltage and the compensated current. The shunt APLC system is implemented with current controlled Voltage Source Inverter (VSI) and is connected to the distribution network for canceling current harmonics. The reference currents are extracted using the Fryze Current Minimization (FCM) algorithm and VSI switching signals are derived from hysteresis current controller (HCC). This method maintains the capacitance voltage of the inverter constant without any additional control circuit. The shunt APLC system is investigated and the performance parameters are obtained under various non-linear and unbalanced load conditions.