a distributed control strategy for load sharing and harmonic compensation in islanded pv-based microgrids

In recent years, the use of photovoltaic (pv) systems has grown significantly in distribution systems and microgrids (mgs). the pv systems are connected to the mg through an interface inverter. however, when multiple pv inverters are paralleled in a mg, load sharing among pv inverters and their coordinated control to compensate for voltage disturbances become critical challenges. this paper proposes a novel control strategy to guarantee power quality in pv-based islanded mgs. in the proposed strategy, each pv system has a primary control level and a secondary control level. the primary control level of pvs consists of fundamental and harmonic virtual impedance loops that improve fundamental power sharing and distortion power sharing among pv inverters, respectively. in the proposed strategy, the secondary control levels along with the primary controllers are implemented locally to reduce disturbances in the communication system. this control level includes voltage and frequency restoration units and a harmonic compensation unit that generates appropriate control signals and directs the compensation of voltage disturbances in the mg load bus. the simulation results have confirmed the effectiveness of the proposed strategy for fundamental and non-fundamental power sharing among pvs and increasing power quality in islanded mgs with different resource capacities.