A New Voltage Sensorless Control Method for a Shunt Active Power Filter for Unbalanced Conditions

Shunt active power filters (APFs) are utilized to correct power quality problems such as harmonic distortion and power system unbalance. Many control schemes for shunt APFs require measurement of both voltages and currents for the calculation of the instantaneous real and reactive power signals. The reference currents for the inverter in the APF are determined from these signals. Proposed in this paper is a voltage sensorless control method for a shunt APF which requires that only currents be measured. The reference currents for the inverter in the shunt APF are determined from the negative sequence components of these measured currents. Simulation and experimental results validate the performance of this control method even in the presence of unbalanced conditions.