Vector-Based Synchronization Method for Grid Integration of Solar PV-Battery System

In this paper, a vector-based synchronization technique is proposed for the synchronization of a solar photovoltaic (PV)-battery system to the grid. In this technique, the three-phase grid and point of common coupling voltages are transformed into two vectors in the
α
–
β
plane. Due to the absence of a phase-locked loop and feedback, the proposed technique is simple, and also instantaneous changes in the voltages are considered here. The grid-connected solar PV-battery system operates in the current control mode, while the islanded system operates in a voltage control. Experimental results are obtained on a grid-solar PV-battery system in grid-connected and islanded modes. The two transitions between these operating modes are also studied in detail. All these test results of harmonics in grid voltages and currents are found satisfactory and in accordance to the IEEE-519 and 1547 Standards.