Nonlinear load sharing in low voltage microgrid using negative virtual harmonic impedance

Harmonic power sharing is important in islanded microgrid due to the presence of excessive nonlinear loads in distribution network. The lack of effective harmonic power sharing techniques may lead to overloading of certain distributed generation (DG) units. The concept of variable negative virtual harmonic impedance to share non-linear load in an islanded microgrid has been proposed recently. This paper presents a negative virtual harmonic impedance technique to share nonlinear load in a low voltage microgrid with complex line impedance. A harmonic droop control based on harmonic output power and the virtual output impedance of the DG is implemented to achieve non-linear load sharing. MATLAB/Simulink based simulation studies are presented to validate the non-linear load sharing capability of the proposed strategy.