An Improved Fast Decomposition-Instantaneous Power Theory Based Inverter Control Strategy for Grid Connected PV System

During faults, voltage sag or contingencies occur on the grid side, it is essential to track the behavior of grid current instantly so that the associated inverters can initiate their control operation immediately. This paper gives insight into an improved inverter control strategy based on Fast Decomposition-Instantaneous Power Theory (FD-IPT) for a grid-connected photovoltaic (PV) system. In this proposed work, the IPT has been chosen to track down the active and reactive power on the instant from the grid response rather than waiting for the average power or a full cycle of completion. Further, the decomposition of the grid current into α-β components followed by time domain positive and negative sequence components in a faster manner helps to extract the instantaneous active and reactive power (PQ) from the ac grid and initiate the instant operation of the inverter. The proposed test system has been prepared in MATLAB/Simulink R2021a environment and validated the test response accordingly.