Energy Optimization of a Series Hybrid Electric Ship Propulsion System

Abstract

The electric ship propulsion system due to its economic advantages and, first of all, better mechanical properties than internal combustion engines (influence on ship manoeuvrability) have gained popularity in recent years. This paper presents an investigation of a series hybrid electric propulsion system where two sources of power are used: a permanent magnet synchronous generator and energy storage battery to supply electric propulsion system, which is a permanent magnet synchronous motor. Controlling the power flow from multiple power sources in a series hybrid mechatronic system is important to increase the energy efficiency of the propulsion system. Developing a suitable power flow control method is difficult due to the nonlinear nature of the power sources in the series system. In this paper a method of energy optimization of the system has been verified which allows to improve energy efficiency by reducing reactive power in the system. In this paper, an analytical study of the mechatronic system of a serial hybrid electric ship propulsion system is carried out based on the analysis of the steady-state electromagnetic and energy relations. The proposed control with energy optimization was compared with the commonly used FOC control. The analytical studies have been confirmed by performing simulation studies in Matlab-Simulink program. The proposed optimization method allows its use not only in ship electric drives but also in other autonomous electric drives using the series topology of the hybrid system.