With the continuous rise in the permeation rate of distributed generation systems such as photovoltaic (PV) power, the intricate interplay between PV inverter controllers and grid impedance characteristics has exacerbated stability challenges in power systems. While significant progress has been made in researching single-stage inverters, there remains a notable gap in the comprehensive impedance modeling of PV inverters. This paper addresses this gap by establishing a high-precision impedance model for a complete single-stage PV inverter using impedance analysis methods. Additionally, it proposes a stability analysis framework for integrating PV grid-connected inverters into the system, leveraging both system impedance ratios and impedance interaction diagrams. To thoroughly investigate this issue, this paper first outlines the architecture of a single-stage three-phase PV grid-connected system and develops a sequence impedance model for the grid-connected inverter, incorporating the PV array. Subsequently, to ensure stable operation, the controller parameters are meticulously designed. The present study investigates the stability of integrating the PV inverter into the system under varying parameters. This is achieved by analysing system impedance ratios and impedance interaction diagrams. Finally, the construction of a simulation model of the PV grid-connected inverter is undertaken on the Matlab platform, with results validating the theoretical analysis.