A Decentralized Control of Autonomous/Grid-Interactive Hybrid Dc/Ac Microgrid Using Two Parallel Ics

Abstract

This paper presents a decentralized control of an autonomous/grid-interactive hybrid DC/AC Microgrid (µG) using battery energy storage (BES) and distributed energy resources (DERs). In DC/AC µG unified with different DERs and BES, the variable output nature of DERs due to fluctuating input characteristics and strong interaction of sources, loads, and primary grid causes variations in dc bus voltage, ac bus voltage, and frequency. Hence, to solve this issue, the proposed control method incorporates a P/Q control, dc virtual droop control, voltage control, frequency droop control, current control, phase-locked loop (PLL), and maximum power point control (MPPT). BES and DERs interface converters are autonomously controlled in the control scheme without communication using the frequency droop method and the bus voltage. Correspondingly the control techniques comprehend different operating modes depending on BES, generations, and the grid. During the switching of two interlinking converters, high-frequency harmonics are created, which is eventually mitigated by LCL filters are employed in the ac bus. The maximum power transfer in interlinking converters (ICs) can be improved using the proposed approach for the input source variations. Simulations are developed in Matlab/Simulink, and it is verified using Real-Time Simulation OPAL-RT to ratify the effectiveness of the proposed control strategy.