Influence of Carrier Phase Difference on Supraharmonics in Grid-Connected Photovoltaic System with Parallel Converters

Voltage source converters (VSCs) can generate supraharmonics in grid-connected photovoltaic system (GCPVS). Parallel VSCs with common AC and DC links have been widely applied, and supraharmonics in GCPVS can show new characteristics due to unsynchronized carrier signals. Therefore, dual-reference dynamic phasors (DRDPs) and dual-reference dynamic phasor sequence component (DRDPSCs) are adopted to analyze the new characteristics of supraharmonics and realize accurate calculation on the relationship between supraharmonics and carrier phase difference. First, the dynamic phasors (DPs) and dynamic phasor sequence components (DPSCs) are transformed into DRDPs and DRDPSCs by implementing double Fourier decomposition. Second, a harmonic analysis model of GCPVS is proposed. Then, the influence of carrier phase difference on supraharmonics is calculated and analyzed. Simulation results verify the correctness of the analyses.