Low voltage ride-through of a two-stage photovoltaic inverter under different types of grid faults

Abstract

Today, with an increase in the share of power produced by the distributed generation especially the wind and solar sources, the standards for connecting these sources to the grid have been updated. According to these standards, the distributed generation sources must stay connected to the grid during fault conditions and must help the grid to come back to normal conditions. In this paper, a method is proposed for controlling the 3-phase 2-stage solar converter during fault conditions. In this method, it has been tried to take into consideration and meet 4 main challenges in controlling the distributed generation sources when a fault occurs. These challenges include: 1) The quality of the injected power into the grid. 2) Control of the current of all phases within their allowed ranges for both balanced and unbalanced faults. 3) Meeting the grid requirements during fault. 4) Using the inverter's maximum capacity to support the grid at the times of fault. The functionality of the proposed method is investigated in MATLAB software and Simulink environment.