Harmonic Resonance Analysis of Single-Phase Photovoltaic Grid-Connected System Based on Output Impedance Model

• 1、State Key Laboratory of Power Transmission Equipment & System Security and New Technology (Chongqing University),Shapingba District, Chongqing 400044, China

Abstract：The potential resonance problem in photovoltaic grid-connected systems has been widely concerned by scholars at home and abroad, at present, most research focuses on three-phase large-capacity photovoltaic power station systems. Based on the fact that single-phase small-capacity distributed photovoltaic system are more widely used in user side, this paper models the output impedance model of a single-phase small-capacity photovoltaic system by linearizing a nonlinear photovoltaic inverter circuit. The model is applied to the resonance prediction and analysis of a multi-parallel residential-side distributed photovoltaic grid-connected system. The simulation results show that the model can analyze the resonance problem in multi-parallel single-phase photovoltaic systems accurately and effectively. Furthermore, the model is used to study the influence of grid impedance, composition ratio of photovoltaic inverters with different control modes and user load on harmonic resonance in multi-parallel photovoltaic inverter systems. The results of the analysis are useful for guiding the rational design of the system and avoiding harmonic resonances.

Keywords： electrical engineering photovaltaic harmonicresonance output impedance Influencing factors of resonance