Issues of electromagnetic compatibility of electric equipment on ships with electric propulsion systems

In recent years, semiconductor converters are widely applied in marine electric power systems. Semiconductor converters are used in ship electric propulsion systems consisting of shaft generator units, a variable frequency drive, and alternators. The use of semiconductor converters results in decrease of power quality in ship networks, in particular, in an increased ratio of non-sinusoidal voltage waveforms (harmonic distortion). Rules of the Russian Maritime Register govern the maximum allowable distortion in the power network for a correct functioning of ship equipment. Improvement of power quality is achieved with a variety of methods including application of filter-compensating devices, three-winding transformers, and electromachine converters. The paper analyzes a single marine power system and circuit solutions for reducing the ratio of harmonics in ship networks.