Frequency Transient Suppression in Hybrid Electric Ship Power Systems: A Model Predictive Control Strategy for Converter Control with Energy Storage

Hossein Enshaei,Viknash Shagar,Shantha Jayasinghe

doi:10.3390/inventions3010013

Hossein Enshaei, Viknash Shagar + Show 1 more

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https://doi.org/10.3390/inventions3010013

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Journal: Inventions	Publication Date: Mar 1, 2018
Citations: 8	License type: CC BY 4.0

Affiliation: Australian Maritime College, University of Tasmania

Abstract

This paper aims to understand how the common phenomenon of fluctuations in propulsion and service load demand contribute to frequency transients in hybrid electric ship power systems. These fluctuations arise mainly due to changes in sea conditions resulting in significant variations in the propulsion load demand of ships. This leads to poor power quality for the power system that can potentially cause hazardous conditions such as blackout on board the ship. Effects of these fluctuations are analysed using a hybrid electric ship power system model and a proposed Model Predictive Control (MPC) strategy to prevent propagation of transients from the propellers into the shipboard power system. A battery energy storage system, which is directly connected to the DC-link of the frequency converter, is used as the smoothing element. Case studies that involve propulsion and service load changes have been carried out to investigate the efficacy of the proposed solution. Simulation results show that the proposed solution with energy storage and MPC is able to contain frequency transients in the shipboard power system within the permissible levels stipulated by the relevant power quality standards. These findings will help ship builders and operators to consider using battery energy storage systems controlled by advanced control techniques such as MPC to improve the power quality on board ships.

Highlights

IntroductionIn view of recent legislation involving the creation of Emission Control Areas (ECAs) [1], ships with electric propulsion have become more of a reality with more cruise ships, ice breakers and various types of service vessels adopting this technology [2]
The transportation industry has experienced many technological advancements over the years.One of the key developments is electrification in the form of electric traction or electric propulsion.In view of recent legislation involving the creation of Emission Control Areas (ECAs) [1], ships with electric propulsion have become more of a reality with more cruise ships, ice breakers and various types of service vessels adopting this technology [2]
This paper has illustrated the integrated modelling of the hybrid shipboard power system comprised of both the mechanical propulsion system and the electrical power system. This model has served as the platform for load change studies involving both propulsion and service loads and the transient effect that they have on the main generator speed and the electrical frequency

Summary

Introduction

In view of recent legislation involving the creation of Emission Control Areas (ECAs) [1], ships with electric propulsion have become more of a reality with more cruise ships, ice breakers and various types of service vessels adopting this technology [2]. Hybrid propulsion is a convenient waypoint between traditional mechanical propulsion and fully-electric propulsion as it combines the two, thereby reducing the need for a complete revamp of the propulsion system in very large ships such as container vessels. In these ships, propulsion load is the most challenging type of load as it forms the largest proportion of the total load in the electrical system.

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