The effect of amplitude fluctuations in utility grid affects the estimated phase angle and frequency by the phase locked loops (PLL). Moreover, the phase angle and frequency estimation loops in PLLs are not decoupled, which leads to inaccurate phase and frequency estimations during amplitude fluctuations in the grid voltage. Moreover, connection of highly reactive loads at the point of common coupling leads to spurious transients in phase angle, which again affects estimated frequency with sudden overshoots. Moreover, connected loads also demean system power quality indices (PQI). Hence, there is a need to decouple voltage-phase angle and frequency estimation loops to minimize the effect of transients in one parameter over the other. Moreover, to adhere to the grid codes, there is a necessity to improve PQI by eliminating dominant harmonics. Hence, this work considers a solar photovoltaic array (SPVA) based grid-tied microgrid with a battery energy storage (BES) connected at the DC link. A multiple reduced order generalized integrator (MROGI) filter-based control is adopted with an improved PLL (IPLL) to minimize the effects of coupling in voltage-phase angle and frequency estimation loops. Simulated results are achieved using MATLAB R2016a to demonstrate system performance with the control.