Full-Order and Simplified Dynamic Phasor Models of a Single-Phase Two-Stage Grid-Connected PV System

Abstract

The dynamic phasor (DP) method is a useful tool for developing simulation-efficient models suitable for system-level analysis. In this paper, two DP models of a single-phase two-stage grid-connected photovoltaic (PV) system are proposed. In the first DP model (DP-Full), the PV array, PV capacitor, boost converter, DC-link, and MPPT (maximum power point tracking) control are modeled. In the second DP model (DP-Simp), the DC-side model is simplified by aggregating the PV capacitor- and boost inductor dynamics into a first-order function while calculating the MPP voltage and current analytically. The accuracy and execution speed of the two DP models are verified by comparing their performance with those of a detailed switching model simulated in an electromagnetic transient program. Simulation and error calculation results show that there is a good agreement between results from the proposed DP models and the switching model. Simulation studies of a two-bus power system demonstrate the computational advantage of the DP-Simp and DP-Full models over the detailed switching model in a multi-converter scenario. The proposed DP models can be used for the fast-paced transient analysis of distribution grids with high PV penetrations.