FOFLL Based Synchronization Scheme with LDLMS Control for Solar Fed Microgrid Feeding Hybrid AC/DC Loads

This work shows the validation of solar photovoltaic (SP) fed three phase microgrid system. Adaptive based leaky delayed least mean square (LDLMS) control algorithm is used in utility interfaced operational mode. This adaptive algorithm has the ability to filter system parameters without actually knowing about the environment where it is employed. Such type of algorithm is employed for this system due to the non-linear (NL) nature of SP fed system. For synchronization, a first order frequency locked loop (FOFLL) is adopted, which utilizes one integrator to generate its orthogonal signals, and are used to estimate the angle and angular frequency. FLL technique has the ability to track system frequency as it varies unlike conventional phase locked loop (PLL), where it needs to be tuned and has lock-in range. The microgrid configuration serves two type of loads- DC load connected across DC link capacitor and NL connected at common point of coupling (CPC).