Control of single-phase UPQC in synchronous d-q reference frame

This paper deals with a single-phase unified power quality conditioner (UPQC) to enhance power quality problem in single-phase systems. A control approach based on synchronous d-q reference frame, for single-phase UPQC, is proposed. For orthogonality and thus to formulate d-q transformation for single-phase system an imaginary β-axis component is considered. In d-q frame, the fundamental component in distorted supply voltage and non-linear load current are achieved as DC variables. The representation of single-phase supply voltage and load current in d-q frame, in an actual hardware system, is also discussed in the paper. The proposed approach is utilized to mitigate harmonics in the supply voltage and load current simultaneously. The UPQC system performance is evaluated by simulation as well as digital signal processor based experimental studies.