Variants of structures of the ship’s electromotive complex with common DC bus-bars

Admiral Makarov State University of Maritime and Inland Shipping, Dvinskaya Str., 5/7, Saint Petersburg, 198035, Russia

^* Corresponding author: saushevav@gumrf.ru

Abstract

Schematic and algorithmic solutions for the design and construction of ship’s electromotive systems of various purposes are considered. The analysis of the existing structures of electromotive complexes, as well as the types of electrical converters used is carried out. The structure of an electromotive complex based on a transformerless structure with common DC bus-bars is proposed. The main goals of improvement are to increase energy efficiency, reliability and survivability of an electric power plant, and lower weight and size characteristics. The proposed structure of the ship’s electromotive complex allows braking the propellers without using additional braking circuits with the redistribution of energy between the propeller electric machines and the dissipation of braking energy in the working medium - water. An algorithm is proposed and mathematical modeling of braking and reverse modes of a propeller electric installation is carried out. Timing diagrams of changes in torque, rotation speed and power on each of the propellers for the proposed algorithm of braking and reverse of propeller motors are presented. It is shown that the synthesized structure of the electromotive complex makes it possible to reduce the emissions of pollutants into the environment, as well as to save fuel within the range of 10÷15%, depending on the operating modes of the ship in comparison with the existing structures of the electromotive systems.