Control Scheme for Three-Phase Four-Wire UPQC in a Three-Phase Stationary Frame

In order to suppress the influences of non-ideal input voltage and non-ideal load, a coordinated control strategy based on ABC stationary frame for three-phase four-wire (3P4W) unified power quality conditioner (UPQC) is introduced. By controlling the series converter as a fundamental sine current source and the parallel converter as a fundamental sine voltage source, the proposed control strategy can make the UPQC carry out all of the control goals: sinusoidal input current with unit power factor, sinusoidal and balanced output voltage with rated value. The experimental results of 10 kVA prototype verify that the control strategy is feasible.