Synchronization and Power Quality Improvement of 2SPV-BES Based Microgrid

Abstract

This paper deals with the control and synchronization of double-stage solar photovoltaic (2SPV)-battery energy storage (BES) based three phase microgrid. The modified damped second order generalized integrator (MDSOGI) current control algorithm is used to feed power to the grid and at the same time it is used to provide phase angle and frequency estimation for the purpose of synchronization. MDSOGI is a modified version of the damped-SOGI structure, where frequency is estimated by integrating a frequency locked-loop (FLL) algorithm that utilizes the quadrature shifted components of the DSOGI structure. It has better power quality (PQ) performance, enhanced load balancing ability, effective harmonic mitigation property due to the band-pass-filter type phase response of the SOGI structure and is robust during frequency deviations. MDSOGI is used to extract the active and reactive fundamental weight components for generation of reference grid currents. Thus, the current control also meets the reactive power demand at common coupling point (CCP). In islanded mode of operation, voltage control mode is utilized and the MDSOGIFLL with the help of phase angle regulator is used to generate local frequency. This system is simulated in SIMULINK/Matlab R2020b and is subjected to various dynamic conditions for validating the satisfactory performance. Total harmonic distortion (THD) is found well within the IEEE-519 standard.