Coordinated Bidirectional Power Flow Management with Power Quality Improvement in AC-DC Hybrid Micro-grid under Unbalanced Scenario

The present day electrical power system is highly complex due to the increase in load demand and distributed generations. Further, the intermittent renewable sources and non-linear power electronic loads connected to the grid deteriorates the power quality of the system. Also, the more and more DC loads like LED lights to save energy consumption are connected to the AC distribution system. These issues can be effectively addressed using the smart micro-grid system. In an individual AC or DC micro-grid, the higher number of AC-DC-AC/DC-AC-DC power conversion stages lead to the increased power losses. Therefore, in this paper, an AC-DC hybrid micro-grid topology is proposed, wherein, AC sources and AC loads are connected to AC grid while DC sources and DC loads are connected to DC grid there by reducing the power conversion losses. The shunt active power filter based 3-phase 4-leg bidirectional interlinking converter using d-q reference current method with PI control is proposed to accomplish the inverter-based & rectifier-based power exchange between AC & DC sub-grids with harmonic current compensation under various grid and load conditions. The analysis is carried out in MATLAB/SIMULINK and results proving the improved power quality.