Stability analysis of grid-connected inverter is the key to the wide application of this controllable power electronic device

and the analysis method based on impedance modeling is usually adopted. When applying the traditional impedance method

the derivation workload is large

and it is difficult to construct the impedance model of complex high-order systems. In this paper

the impedance analysis method based on multi-domain mapping is adopted. Firstly

the detailed models of typical components such as three-phase grid-connected inverters and synchronous generators are established. Based on the differential-algebraic equations of the components

the general transformation expressions of the coefficient matrices of the discrete state space model are derived. Secondly

combined with the network topology information

the equivalent aggregation admittance/impedance modeling of the system ports can be automatically realized by computer programming according to the mapping relationship between the discrete domain and the continuous domain

avoiding a large amount of high-order and complex symbolic operations in the process. Based on the constructed zero-pole-gain form frequency domain model

the generalized Nyquist criterion can be used to further analyze the influence of parameter settings on system stability. The simulation verifies the effectiveness of this method in impedance/ admittance modeling of renewable energy grid-connected systems and the correctness of theoretical stability analysis. Compared with other impedance modeling analysis methods

it is more efficient and suitable for large-scale systems.