A multi-function single-phase voltage source inverter with current harmnonic elimination and voltage regulation features

This paper presents a multi-function of single-phase voltage source inverter for current harmonic elimination and voltage regulation at the point of common coupling (PCC). The inverter is operated as an active power filter to eliminate harmonic and compensate reactive power under the normal utility voltage condition. In this condition the line current is almost unity power factor. A dc-link voltage controller is used in the outer loop to maintain constant dc-link voltage, and a hysteresis comparator is used in the inner loop to track reference line current. If the voltage sag or swell is detected at the PCC, the inverter is operated as a static synchronous reactive compensator to maintain PCC RMS voltage constant. The inverter should supplies capacitive (or inductive) current to compensate the voltage variation due to the effect of voltage sag (or swell). The compensated current that is orthogonal to the PCC voltage is obtained from a RMS voltage controller. Some simulations results are presented to verify the effectiveness of the control scheme.