Structure of the ship's electromotive complex with Dual DC buses
A perspective structure of the ship's electromotive complex with dual DC buses, which allows you to increase the reliability and survivability of the electric power system, to improve the operational, energy and weight and size characteristics of the electric propulsion system, is presented in the paper. In addition, such a structure makes it possible to reduce pollutants emissions into the environment, as well as to realize fuel savings in the range of 10-15%, depending on the operating modes of the vessel, compared with the existing structures of electric propulsion systems. The proposed structure of the ship's electromotive complex allows braking the propellers without using the additional brake circuits with energy redistribution between the propulsion electric machines and the dissipation of braking energy in the working medium - water. Using the canonical polynomial of the seventh degree, an analytical description of the limiting reverse characteristic of the propeller is given. An algorithm for the braking and reverse of a rowing electric installation is proposed and a diagram with the power flows directions is shown. A mathematical description of the braking and reverse modes of the propulsion electric installation is given, and the control algorithms for the proposed propulsion electric installation with two propellers during braking and reverse are synthesized. Timing diagrams of changes in torque, speed and power on each of the propellers for the proposed algorithm for braking and reverse of the propeller motors are presented. The variants of the structure diagrams of the ship's electromotive complex with dual DC buses using multilevel voltage inverters, as well as with the possibility of power supply from a single power plant, both a propulsion electric installation, and consumers of their own needs, are presented.