Electric Ship Research Articles

Design Principle Considering Structural Mutual Effects of Double-Stator V-Shape-PM Vernier Machines for Electric Ship Propulsion

This paper proposes the design principle considering structural mutual effects of double-stator V-shape permanent-magnet (DS-V-PM) vernier machines for electric ship propulsion (ESP). Due to the flux concentration effect of the V-PM configuration, the double stators can be divided as a major and a minor stator, considering the different torque generation capability. Cooperation mutual effects between the double stators, V-PM arrangement and vernier machine topology are specifically included in the machine design principle exploration. To illustrate the design principle, first, a unified design principle is deduced, fit for general PM vernier machines. Then, a multi-step optimization strategy with auxiliary of sizing equations is presented, focusing on the parameter cooperation with flux modulation effect. Furthermore, through electromagnetic performance comparison, specific mutual effects of the DS configuration, DS angle shift, V-PMs and barrier structure are clearly summarized. Based on the DS machine design, the multi-mode operation for ESP system is introduced and analyzed. The normal/faulty cruise mode and charging mode are included to realize bi-directional operation. Prototype experiments are carried out for verification of the proposed machine design and operating strategy.

Statistical Models for Condition Monitoring and State of Health Estimation of Lithium-Ion Batteries for Ships

Battery systems are increasingly being used for powering ocean going ships, and the number of fully electric or hybrid ships relying on battery power for propulsion is growing. To ensure the safety of such ships, it is important to monitor the available energy that can be stored in the batteries, and classification societies typically require the state of health (SOH) to be verified by independent tests. This paper addresses statistical modelling of SOH for maritime lithium-ion batteries based on operational sensor data. Various methods for sensor-based, data-driven degradation monitoring will be presented, and advantages and challenges with the different approaches will be discussed. The different approaches include cumulative degradation models and snapshot models, models that need to be trained and models that need no prior training, and pure data-driven models and physics-informed models. Some of the methods only rely on measured data, such as current, voltage and temperature, whereas others rely on derived quantities such as state of charge (SOC). Models include simple statistical models and more complicated machine learning techniques. Insight from this exploration will be important in establishing a framework for data-driven diagnostics and prognostics of maritime battery systems within the scope of classification societies. Conflict of Interest Statement The authors declare no conflicts of interest.

A comprehensive energy analysis of a hybrid motorization for small/medium boats

Small/Medium boats are considered as favourite maritime transportation, and they are mostly propulsed by Outboard Motors. Boats are designed for recreative, fishing and surveillance purposes, however in tropical undeveloped countries boats are employed for different applications such as passenger and goods transportation fairly away from nominal power engine, which lies from 8 to 12% engine efficiency. The present survey aims to develop a novel navigation perspective in a power and efficiency analysis of Plug-in Hybrid Electric Ship (PHES) 1. An internal combustion engine (ICE) is converted in hybrid propulsion system (HPS) coupling an electric motor powered by batteries through an electric DC bus device in a parallel configuration system, in order to increasing the traveled distance to fuel consumption ratio. Parameters such as boat size, engine hybrid configuration, were simulated on a schematic model system following an actual navigation route drawn, improving a 25-30% overall system efficiency respect nominal engine performance.

Selective Protection Analysis Method for DC Power Plant Propulsion Systems in Electric Ships

Selective Protection Analysis Method for DC Power Plant Propulsion Systems in Electric Ships

A Two-Layer Energy Management Strategy of Fuel Cell Hybrid System in Electric Ships

A Two-Layer Energy Management Strategy of Fuel Cell Hybrid System in Electric Ships

A suggestion for space harmonic injection into motor current to reduce propeller vibration

Propellers produce fluctuating thrust and torque as they rotate in a non-uniform wake field. They contribute most of the vibration and noise generated by the propeller and can lead to mechanical damage to shafts and bearings. Recently, the demand for electric propulsion ships has increased. As the torque and speed fluctuations are generated in marine propellers, harmonic components in the current and voltage of the propulsion motor occur and lead to increased losses, device degradation, and torque pulsations. In this study, a harmonic injection method is proposed to reduce the impact of motor and mechanical vibration caused by the fluctuating load torque of the propeller. A harmonic component is applied to the current of the motor to generate a motor torque with a different phase of the same magnitude as the variation of the load torque of the motor. In this study, a computational fluid dynamics simulation was performed to obtain the torque of the target vessel, medium range tanker, and a MATLAB Simulink was used to model the motor simulation. It was found that the harmonic injection method can reduce the mechanical torque fluctuation of the motor by 87%.

Power Control Strategy Optimization to Improve Energy Efficiency of the Hybrid Electric Propulsion Ship

Power Control Strategy Optimization to Improve Energy Efficiency of the Hybrid Electric Propulsion Ship

Adaptive Control of a Two-zone Model of Electric Ship Power Electronics Power Distribution System

Power system operations must be robust to unexpected non-ideal conditions. In an attempt to create more robust Power Electronic Power Distribution Systems in ships in the event of changes in the ambient characteristics such as temperature or load changes, a Model Reference Adaptive Control was implemented. Our approach was based on distributed control of the converters in a two-zone model and for the two types of converters present in the system. This work used adaptive law based on instantaneous cost to modify the existing control coefficients in an online mode. The result is that the designed adaptive control can readjust the transient and steady state responses of the converters when they deviate from their original forms in case of any of the unexpected conditions.

Multiphysics Modeling and Co-Simulation of Ship Electric Power and Propulsion Systems for Virtual Testing and Verification

Multiphysics Modeling and Co-Simulation of Ship Electric Power and Propulsion Systems for Virtual Testing and Verification

Line-Spectrum Extraction of Ship Electric Field Based on SVMD-AAMPSR

Line-Spectrum Extraction of Ship Electric Field Based on SVMD-AAMPSR

Hybrid PV and Fuel Cell Generating System for Shipboard Applications Based on Optimal Dispatch Evaluator Algorithm

The construction of an Energy Management System (EMS) for ships has been designed to improve the electrical performance of cruise lines. According to the target requirement, the specified electrical plant is an integrated power system characteristic of contemporary electric ships. Battery backup, low performance, and voltage instability are the drawbacks of the existing method. To overcome the limitations of the proposed method-based Photovoltaic (PV) renewable source using SEPIC DC–DC converters and a bidirectional fuel cell as an additional input power source. Power generation from the two different input sources is controlled through a DC bus and conversion through a centralized high-gain DC–DC converter. In this conversion, Pulse Width Modulation (PWM), which is the maximum power obtained using the optimal dispatch evaluation algorithm using an Artificial Neural Network (ANN), is obtained by adjusting the duty ratio of the Single-Ended Primary Inductance DC–DC converters (SEPIC). The electrochemical power source is a fuel cell. Hydrogen and oxygen are combined in fuel cells to create electricity, along with the consequences of heat and water being transformed into mechanical energy; in the battery management system, the battery is employed as an energy storage system to regulate any power imbalance or excess while taking the battery’s state of charge into account Electric Ships (AESs). The outcomes of the MATLAB Simulink output, fuel cell and battery storage performance analysis, efficiency, and THD analysis are summarized as follows.

METHODS OF CONTROLLING ELECTRICAL ENERGY QUALITY OF SHIP ELECTRICAL ENERGY SYSTEMS

METHODS OF CONTROLLING ELECTRICAL ENERGY QUALITY OF SHIP ELECTRICAL ENERGY SYSTEMS

The electro-thermal behaviors of the lithium-ion batteries corroded by the salt spray environment

Although the application of lithium-ion batteries in the marine environment such as electric ships and other energy storage equipment, has gradually flourished in recent years, the effect of the special salt spray environment on the cells has not been carefully revealed since it may pose a corrosive threat to the metallized cells. In this paper, the electrochemical performance, aging mechanism, and thermal behavior of the cells after subjecting to different salt spray times are investigated experimentally. The results show that the corrosion morphology of cells is increasingly serious with the salt spray time, destroying the internal structure of the battery and accelerating its aging. The capacity decay mechanism is mainly due to the loss of active material (LAM), while the contribution of the loss of available lithium inventory (LLI) gradually increases and tends to prevail upon the former as the corrosion time prolongs. Findings also show both a larger state of charge and longer salt spray time will result in a much higher battery temperature during the cycling process. The maximum temperature of LIBs with 100 % SOC and salt spray time of 40 h reaches 36.23 °C during the 50th cycle, while that for 0 % SOC is only 30.56 °C. Therefore, the corroded cells age faster, generates more heat, exhibits worse safety performance, and is more likely to cause thermal runaway and other safety issues than the normal ones.

Optimization design of hybrid energy storage capacity configuration for electric ship

Electric propulsion has gained significant popularity in the marine vessel industry due to its numerous advantages. One of the key challenges faced in this domain is effectively managing the fluctuation of power grid caused by sudden load changes. While energy storage systems offer a viable solution, striking the right balance between cost and benefit remains a complex task. To address this issue, establish an optimization model and constraint conditions for capacity configuration of hybrid energy storage systems, and propose a decision-making method based on NSGA-II algorithm and cost-effectiveness method. To address the issue of NSGA-II algorithm being prone to local optima and premature convergence, chaotic thinking and adaptive crossover operators are introduced to improve the NSGA-II algorithm; In order to obtain the optimal configuration scheme from the obtained Pareto optimal solution set, a decision method based on cost-effectiveness was adopted to further analyze the bias between the Pareto optimal solution set and each objective. By comparing the decision results with the ideal solution (TOPSIS), the optimal capacity configuration scheme was obtained.

Optimization of river container port-access transport based on the innovatively designed electric ship in the Yangtze River Delta

In order to increase the share of the container port-access transport of river shipping and reduce the carbon emissions of container transportation, this study innovates the design of wide and shallow draft river ship and its electric power system based on the navigation condition of the rivers in the Yangtze River Delta (YRD) with the objective of raising the advantage in river shipping to truck transport. To validate the ship's practicability, we incorporate the carbon quota of container port-access transport as a constraint and build a model to optimize the river liner service for container port-access transport. The case study reveals that the adoption of innovative 48 TEU electric river ship for container port-access transport will be associated with a rise in the mode share of river liner shipping from 16.1% to 20.0%, a decrease in carbon emission by 0.124 million tons and a decrease of 0.358 billion CNY in container port-access transport in the YRD, while the higher the carbon tax price the more the modal shift will be, however, since the carbon emission cost is a part of the total transport cost, the total transport cost exhibits an upward trend.

Optimization and analysis of Sic reinforced copolymer blend composite structural springs

The design of lightweight leaf springs plays a crucial role in reducing fuel consumption and improving vehicle comfort by minimizing road shock transmission and vibration. Composite materials have shown great potential in significantly reducing leaf spring weight. epoxy, being a desirable thermoset polymer widely used in various applications such as electrical devices, ships and automobiles, exhibits limitations in terms of brittleness, fracture resistance and impact strength. To overcome these drawbacks while preserving its beneficial properties, epoxy can be blended with other polymers and reinforcements. In this study, polysulfide (PS) was selected as a suitable solution to enhance epoxy brittleness, offering an effective yet underutilized approach. Furthermore, the incorporation of silicon carbide (Sic), known for its superior characteristics, aimed to further enhance the mechanical properties of the epoxy-PS copolymer blend. The microstructural analysis was inspected using Fourier transform infrared. The blending and reinforcement process followed a Taguchi L8 static design to evaluate the impact of different composite blending percentages (represented as input factors) on leaf spring tensile strength, damping properties, impact resistance and hardness (represented as responses). The responses were analyzed using S/N ratios, ANOVA, main effect plots and interaction plots, while regression equations were employed to predict the responses under varying factors. The analysis demonstrated a robust model for manufacturing leaf springs. Experimental results indicated a 7.4% reduction in hardness with the addition of PS polymer. Conversely, reinforcing the epoxy-PS copolymer with 10–20% wt. of Sic resulted in a 3–5% increase in hardness. The natural frequency of the composite exhibited a gradual decrease upon the incorporation of PS and Sic. Evaluating the damping ratio revealed that the maximum value was achieved when the epoxy-PS copolymer was reinforced with 20% Sic. Additionally, while the copolymer blend displayed the greatest logarithmic decrement, epoxy exhibited the highest damping frequency.

Thermal runaway behaviour and heat generation optimization of the marine battery cabinet based on module thermal analysis

Currently, the application of lithium-ion batteries in electric vehicles has become common in recent years. Considering the adjustment and transformation of the future energy structure, the use of electric ships is increasing; however, the problem of heat production from the battery cabinet of electric ships must be solved. Therefore, in this study, the multi-scale and multi-domain solution method was used to analyse the heat production and heat transfer of a module-level battery to calibrate the basic calculation model in this study. A double-layer cooling arrangement was proposed to optimise the heat production of the model, which controlled the heat production rate of the battery module to be within 0.00497 K/s. Based on the thermal runaway (TR) module, a three-layer marine battery cabinet was visually analysed for the first time, and the influence of TR on the upper and lower layers and the thermal spread behaviour of the battery pack in the middle layer were studied. The results indicated that the temperature change in the battery in the first layer was more significant than that in the third layer. Furthermore, the proposed double-layer cooling scheme controlled the temperature of the battery in direct contact with the heat source to within 324.4 K. The findings of this study provide insights into the TR behaviour of a marine battery cabinet and its influence on heat generation as well as guidance for the thermal management of electric marine battery cabinets.

Modelling and Simulation Analysis of the Fuel Cell Hybrid Propulsion System

Under the pressure of global energy shortage and severe environmental pollution, using new energy in ships will become the mainstream direction of future development. Compared to traditional single fossil fuels, the hybrid system composed of clean energy improves overall cleanliness. Hybrid power design has also attracted widespread attention in academia and industry. Therefore, this article introduces a hybrid propulsion system for ships. It combines Proton-exchange membrane cell (PEMFC) and cell. A simulation model for the propulsion system of hybrid electric ships was established in the MATLAB/SIMULINK simulation environment. It analyzes the ship’s operating speed and power under different operating conditions and allocates the operating power to the hybrid power system through an energy control strategy. Finally, it compares and analyzes the optimization potential and methods of hybrid power systems. The results indicate that the modeling method and energy management strategy used in this article can effectively simulate the load changes and energy allocation of ships under different operating conditions, improving the stability and efficiency of fuel cells.

Design and Analysis of an Electric Motor Cooling System for a Small Electric Propulsion Ship

Design and Analysis of an Electric Motor Cooling System for a Small Electric Propulsion Ship

Effectiveness of Electric Propulsion Ship with Solar PV Control Toward Cleaner Shipping in South Korea

Effectiveness of Electric Propulsion Ship with Solar PV Control Toward Cleaner Shipping in South Korea