Restraining non-sinusoidal V/I output via adaptive droop control in autonomous AC microgrids

• Investigating devices and techniques that calculate, extract, absorb, suppress, and reduce P/Q power pollution in Microgrids equipped with Distributed Generation and renewables. • The adaptive virtual impedance droop control structure studying to contribute the fundamental and dominant positive- and negative-sequence virtual voltage components to compensate for unbalanced voltage in PCC, and output V/I harmonic affected by non-linear load characteristics in steady-state. • Illustrating the harmonic compensators from the outlook of the filters controlled in frame of adaptive virtual impedance droop control in Microgrids equipped with Distributed Generation. The power quality concerns in an islanded microgrid including V/ f regulation and sustainability for the customer- side, generation efficiency, and P/Q power sharing are revealed when facing mismatched sources' output impedances. Connecting the critical loads such as non-linear and unbalanced loads to microgrid provokes nonlinear output V/I characteristics while leading to background harmonics in the grid-side. The target of this article is to review the comprehensive concepts of self-organizing droop control in the path of virtual impedance to reduce the harmonic and unbalanced components along with challenges and opportunities of least developed techniques. The PI and PR controllers in dq and αβ frameworks (respectively) have been studied as the most flexible local supplemental controllers in detail. Also, this study has been given some of the control schemes the once over to share the destructive circulating current among the units as a kind of harmonic independent of the load components. Also, active and passive filters have been investigated to obliterate reactive power unclean components. Moreover, the analysis of economic issues and methodology of harmonics compensation optimization algorithms has been discussed. Finally, the success rate for reducing THD and VUF of the reviewed techniques has been concluded through numerical charts.