Effect of Supply Voltage Asymmetry on IRP p-q- Based Switching Compensator Control

Abstract — The paper presents results of a study on how the supply voltage asymmetry affects the reference signal for switching compensator control, in a situation when this signal is generated using the Instantaneous Reactive Power (IRP) p-q Theory. According to the IRP p-q approach, the compensator should compensate instantaneous reactive power and the alternating component of the instantaneous active power of the load. The paper demonstrates, however, that in the presence of the supply voltage asymmetry, even an ideal, unity power factor load has an instantaneous active power with a non-zero alternating component. According to IRP p-q Theory-based approach, it should be compensated and this requires that a distorted current be injected into the distribution system. It means that the algorithms based on the IRP p-q Theory generate, in the presence of the supply voltage asymmetry, an erroneous reference signal for the compensator control. Index Terms- Active harmonic filters, active power filters, harmonic suppression, instantaneous reactive power, currents ’ physical components; CPC. I