ASZ-3LAD Control for Single-Stage Solar PV-Battery Based Microgrid with Enhanced SOGI-FLL Synchronization

This paper deals with the grid synchronization and power feeding of single-stage solar photovoltaic-based microgrid system. It is well understood that set-point controllers have stability margin issues. Thus, adaptive algorithm-based controllers are preferable. An adaptive step size leaky-least-logarithmic absolute difference (ASZ-3LAD) algorithm is employed for grid-power injection control. The objective of the ASZ-3LAD algorithm is to meet active and reactive power demands of the loads connected to the microgrid and feeds the rest of the power to the utility without compromising power quality. For synchronization an enhanced second-order generalized integrator frequency locked loop (En-SOGI-FLL) method is used to reduce current spikes. En-SOGI-FLL uses only the quadrature shifted outputs of the SOGI structure to estimate the angular frequency of the input. The dynamic behaviour of the microgrid is simulated in MATLAB/Simulink R2020b. The injected grid current’s power quality (PQ) is within the IEEE-519 standard.