Harmonic Virtual Impedance Control in Islanded Microgrids for Power Sharing and Suppression

Distributed generators (DGs) can be connected to loads in practical islanded microgrids (MGs) using a wide variety of feeder impedances. Mismatched line impedance and various nonlinear load limitations present challenges for the technology that is currently used for controlling distributed generators in microgrids with complex architectures. This study presents a method for generating harmonic virtual impedance as a response to the issues that have been described above. This method lowers the harmonic voltage at the point of common coupling (PCC), which enables harmonic current sharing at the same time. The approach can be broken down into two distinct components. First, the constraints of harmonic current sharing are formulated according to the topology of the microgrid. Next, the optimal harmonic virtual impedance value is determined through the optimization algorithm, which initially reduces the harmonic voltage of the PCC. After that, the disruption of the PCC harmonic voltage is corrected by voltage compensation block, which leads to an even more significant improvement in the voltage quality. In conclusion, the applicability and efficiency of the method are demonstrated through the use of experimental works.