CONTROLLING, MODELLING AND SIMULATION OF THE HYBRID ELECTRIC PROPULSION SYSTEM USED FOR TUGBOAT

Abstract

The recent trend to design more efficient and versatile ships has increased the variety in hybrid propulsion system. To improve performance with these architecture, various control strategies is needed. Now a day the demand of the renewable energy resources is high and due to these demand various alternative fuels comes into picture and variable speed technology developed which will help most. This paper includes various control strategies to accomplish its controlling and correspondingly system information . To fully utilise hybrid propulsion systems, one must first comprehend their concepts of operation, as well as their constituents as well as the factors that affect its development and the means by which it is produced to keep them under control[1]. In accordance with this An LNG(liquefied natural gas) is used as fuel in place of heavy fuel and accordingly gas engines which is Bergen c series, instead of DF engine basically DF engines are used when enough fuel is not sufficient for complete voyage, is used which restricts environmental pollution A battery storage also add its importance in fuel reduction while low loads .A concept of variable speed is arise due to study of Tug boat load profile so that DFIM (Doubly fed induction machine) ,which basically reduces the fuel consumption considerably[2] . Basically A good propeller help in reducing effort of machine so that Azimuthal PM thrusters are used which gives better control and maneuverability. A Scalar control has long been used as a simple means of controlling voltage, current, and frequency, and it is still used in major controllings due to its ease of use.where a quick response to speed and torque commands isn't needed[3]. A Space vector control strategy is used for better active, reactive power and of its better precise steady-state output and low power ripple.In the sequence a modeling of each component is try to be done and corresponding simulation of the whole system is to be made ,which give a simplified view of the each element.