Analysis of Distributed PV Harmonic Characteristics Based on Harmonic Coupling Admittance Matrix Model

Because the wider application of power electronic converters used in distributed photovoltaic(PV) grid-connected in the distribution network, the harmonic problem caused by the high proportion of distributed PV is becoming more prominent. The harmonic interaction with other complex harmonic sources in the distribution network is more obvious. In this paper, the harmonic interaction mechanism of distributed PV is studied. Firstly, the harmonic transfer function matrix model of the three-phase LCL grid-connected converter based on harmonic state space(HSS) is established. Then, based on the AC/DC harmonic coupling admittance amplitude diagram of the converter, the AC/DC harmonic coupling relationship is studied. Finally, the AC/DC harmonic coupling relationship is demonstrated in the simulation result and the actual measured result. It provides the support for the PV harmonic source modeling study.