Extremum-Seeking Control for Harmonic Mitigation in Electrical Grids of Marine Vessels

This paper focuses on the minimization of the harmonic distortion in multibus electrical grids of marine vessels using a single active power filter. An active power filter is commonly used for local harmonic mitigation. However, local filtering may lead to a “whack-a-mole” effect, where the reduction of harmonic distortion at the point of installation is coupled to an increase of distortion in other grid nodes. The few existing filtering methods that consider system-wide mitigation are based on an accurate model of the power grid, which may not be available if the complexity and the scale of the grid are large. In this work, we investigate the use of an extremum-seeking control method to optimize the injection current of an active power filter for system-wide harmonic mitigation. Because the extremum-seeking control method is model-free, it can be used without knowledge of the electrical grid. Moreover, the method can be implemented on top of the existing approaches to combine the fast transient response of conventional harmonic-mitigation methods with the optimizing capabilities of extremum-seeking control.