A novel control strategy to operate inverter based distributed generation unit as shunt APF in an islanded microgrid

This paper proposes a novel control strategy for harmonic current filtering in an inverter-based-islanded microgrid, to minimize harmonic propagation in the distribution network. In most of the reported works, the nonlinear load is shared among the distributed generation units by altering either the effective line impedance or the inverter output impedance. In the proposed control scheme, the DG, which is in close proximity to the nonlinear load, is controlled to support the maximum harmonic load demand. In an isolated power system, with decentralized control, all distribution units operate in voltage controlled mode to share active and reactive power. In the proposed control, harmonic current filtering is achieved by controlling the harmonic content of inverter output current. Thus, the proposed control scheme controls the inverter output voltage at fundamental frequency and the inverter output current at harmonic frequencies. The independent control of linear and nonlinear components offers maximum flexibility of power distribution. The feasibility of the proposed scheme is demonstrated using Matlab/Simulink based simulation studies.