Resonance analysis and detection of the clustered grid-connected PV system

Abstract:
The resonance of the clustered grid-connection photovoltaic (PV) system is different from that of the traditional PV system. Resonant frequency of the latter is determined by the LCL filter parameters. Resonant frequency analysis of the former will be complicated which is affected by the resonant coupling of the other grid-connected inverters and the grid. In order to detect the resonance signal, this paper proposes a new method based on wavelet transform (WT) and Hilbert-Huang transform (HHT). Finally, the resonance signal is the harmonic whose amplitude is positive growth. Simulation and experimental results verify the validity of the proposed method.