Study of marine power train system through mathematical modelling of various electro-mechanical components

• Main Author: Khor, Boon Siang
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Mechanical engineering::Control engineering
• Online Access: http://hdl.handle.net/10356/60228
• Institution: Nanyang Technological University

Modeling and simulation of power generation and energy storage system onboard an electric propulsion harbor tugboat by using MATLAB/Simulink is presented in this report. Additionally, control systems have been developed to enhance the power generation process by minimizing fuel consumption. The Simulink model in this project includes diesel engine generator sets, battery energy storage system, control systems and a load power demand profile. Main motivations of doing this project are to reduce fuel consumption in power generation process and to meet emission regulations set by IMO. As the magnitude of load power demand for harbor tugboat varies largely throughout its operation, a lot of fuel would be wasted due to low fuel efficiency of diesel engine operating outside its optimal operating region. Thus enhancement of power generation process has been carried out with some examples presented in this report and the concepts are included in development of the control systems. The power generation system consists of five diesel engine generator sets with different rated power. They are modeled by using simplified first order transfer function for ease of simulation and system level analysis. A control system has been established for the power generation system to schedule optimal power output of each diesel generator set based on system total power demand to minimize total fuel consumption. The battery energy storage system is composed by 36 units of battery module. Control systems have also been developed for the battery system to control its operation mode and magnitude of battery power being charged or discharged. The load power demand profile is used as system power consumer in the simulation. The load profile is a summary of harbor tugboat’s load power demand data that is recorded during operations in the marine and offshore industry. Thus the load profile includes a few step increases and step decreases of load power demand in an operation cycle. DC voltage system is used in the simulation and the system voltage is converted from total system power by applying capacitor model. A PI controller is employed to adjust the total power output of diesel generator sets based on fluctuation in the system voltage. With the simulation results shown at the end of this report, signals of total generated power, battery power, state of charge of the battery system, system voltage, and fuel efficiency of each diesel generator set are analyzed and discussed.