Research Of Marine Electrical Network Stabilization Influenced By The Electric Propulsion System

Ship electric power system is a stand-alone power system, which has small generating capacity and large load capacity relatively. There will be greatly affected with the load fluctuations in the stability of the electricity grid. Electric propulsion system is the most important load in ship power system, accounting for more than 60% of generating capacity. It is significance to study the operation of propulsion that impact on the ship power system. To analyze the stability of generator is an improtant part of stability analysis in the ship power system, and is the main work of this paper also.This study taking into account the dynamic characteristics of generator, propulsion motor and propeller. Established the generator and its control systems and electric propulsion system model respectively, finally achieving the right combination of ship power system simulation.First of all, an important component of the system modeling:(1)Taking into account the disturbances to the motor by propeller,established permanent magnet synchronous motor control system model using vector control method and SVPWM pulse width modulation techniques.(2)Taking into account the relationship between ship motion and the propeller and the interaction between ship and propeller, established a unified ship-propeller system model.(3)Taking into account the system load fluctuations to the generator terminal voltage and power system voltage stability requirements, in the establishment of generator and control system using PID closed-loop control model of excitation control link, forming the main power and control of bodypower model.Then simulated the electric propulsion system and the generator excitation control system and analysed the dynamic features in the MATLAB/SIMULINK environment.Finally, combined the "power" model and "load" model and integratly simulated the generator terminal voltage in the operating condition of electric propulsion system starting at full speed, grading starting, direct brake, braking, and direct reverse grading.