Flexible harmonic suppression method for model predictive controlled virtual synchronous generator in microgrids

In a microgrid, DC/AC converters based on virtual synchronous generator (VSG) are essential for delivering high-quality electrical power to both local loads and the AC grid, but the harmonic suppression ability of VSG is challenged by the AC grid harmonics and nonlinear loads. Thus, in this study, for a microgrid converter with the model predictive controlled virtual synchronous generator (MPC-VSG), the mechanism of current and voltage harmonics at the point of common coupling (PCC) is deeply analysed, and an impedance reshaping-based flexible harmonic suppression method is proposed. By introducing an appropriate and predictive voltage feedforward, we enhance the virtual impedance at the grid port, enabling flexible regulation of PCC voltage quality and grid current quality. Simulation results validate the efficacy of the proposed control methodology.