Converter Control During Low Voltage Ride Through Operation for Grid-Interfaced Solar PV Battery Assisted System

The grid-interfaced solar photovoltaic (PV)-based distributed generation system (DGS) installations have increased tremendously. The penetration of DGS into the grid requires the DGS converter to pose the fault ride through capability. It demands the converter to remain connected during sags and to provide reactive power support to the grid. In this article, the grid-interfaced solar PV battery assisted system for balanced as well as unbalanced power generation along with low voltage ride through (LVRT) functioning is presented. An efficient and simple control technique is developed for the system, such that the DGS converter stays connected to the grid under fault conditions till the LVRT required standards are fulfilled. The dc-link voltage variations and LVRT control are achieved by the battery energy storage bidirectional dc–dc converter. The positive sequence grid current components are considered to meet the LVRT standards. The controller ensures that the DGS converter currents are within the rated limits. The presented control strategy of DGS converter operation during voltage sags and unbalanced power generation is simulated and validated in MATLAB/Simulink. The developed topology and its control are validated through test results.