Ship electromotive system with common DC buses

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

^* Corresponding author: ep-gumrf@bk.ru

Abstract

The universal structure of the ship’s electromotive system with common DC (direct current) buses is proposed. It is shown that this structure allows: improving operational, energy, environmental and massdimensional characteristics of the motive system; increasing the reliability and survivability of the ship’s electric power system; braking propellers with the transfer of braking energy to consumers of its own needs or to the energy storage; redistributing energy between propulsion electric machines with the dissipation of braking energy in the working environment; providing fuel economy in the range of 12^15 % depending on the modes of operation of the ship in comparison with the known structures of electric propulsion systems. Analytical dependences that allow choosing the voltage level of the electric generator and coordinating it with the level of nominal voltages on the propeller motors and other load connected to the voltage inverters are obtained. A function for the analytical description of the limiting reversible mechanical characteristic of the propeller is synthesized. The mathematical description of the braking and reverse modes of the propulsion electric plant is given. Synthesis of algorithms of control of propulsion electric plant with two propellers at braking and reverse is carried out. The time diagrams of the torque, speed and power changes at each of the propellers for the proposed algorithm of braking and reverse of the propeller motors are presented.