Shipboard Microgrid Research Articles

Operational Resilience Assessment in DC Shipboard Microgrids: A Short-Term Energy Imbalance Approach Based on Frequency-Domain Metrics

Operational Resilience Assessment in DC Shipboard Microgrids: A Short-Term Energy Imbalance Approach Based on Frequency-Domain Metrics

A maiden application of an MGO-tuned cascade controller for the secondary frequency control in biogas-powered marine shipboard microgrid

The use of renewable energy sources in marine microgrids has become crucial to limiting the emissions from the shipping industry. Hence, sources like biogas, solar photo-voltaic, sea wave energy, etc. are being integrated rapidly into marine microgrids. In this study, a novel implementation of cascaded controllers like 1 + PI-TID and 1 + PD-PI is modelled for the secondary load frequency control of the shipboard system. The proposed controllers are then tuned with a newly developed metaheuristic algorithm i.e. mountain gazelle optimisation. Moreover, a comparative study is done with other newly developed algorithms. The performance of these controllers is checked in diverse scenarios. The proposed method gives a 23.79% and 54.07% increase stability for the conventional PI controllers. Furthermore, for studying cyber-attacks in the proposed system, various durations of communication delay are introduced and its stability is evaluated. Finally, sensitivity and uncertainty analysis is performed for the validation of the effectiveness of the proposed controller.

Containment-Based Distributed Secondary Control for AC Shipboard Microgrids under General Noise

This paper investigates the secondary control problem of shipboard microgrids (SMGs) with a high percentage of new energy sources under general noise. Firstly, a polymorphic SMG model is constructed, which enables the software-defined functionality of the control strategy and allows heterogeneous distributed generators (DGs) in AC SMGs to exchange packets of different types. Secondly, due to the presence of highly dynamic and high-power loads in the SMGs, a containment-based distributed secondary control strategy is proposed to improve the flexibility of the DG voltage regulation. Then, considering the complexity and diversity of disturbances during ship navigation, general noise is introduced instead of white noise to describe various disturbances. Furthermore, based on the random differential equations (RDEs), the NOS stability of the proposed strategy is proved using Lyapunov theory, which proves the effectiveness of the containment-based distributed secondary control strategy under general noise. And, the containment error is obtained to prove that the voltage and frequency of the system converge to the convex hull spanned by the virtual leaders, ensuring the high quality of the power supply. Finally, the validity of the proposed containment-based strategy is verified by an AC SMG model with four DGs in three cases.

Robust Passivity-Based Control for Interleaved Bidirectional DC–DC Power Converter With Constant Power Loads in DC Shipboard Microgrid

Robust Passivity-Based Control for Interleaved Bidirectional DC–DC Power Converter With Constant Power Loads in DC Shipboard Microgrid

Study of an LLC Converter for Thermoelectric Waste Heat Recovery Integration in Shipboard Microgrids

Static waste heat recovery, by means of thermoelectric generator (TEG) modules, constitutes a fast-growing energy harvesting technology on the way towards greener transportation. Many commercial solutions are already available for small internal combustion engine (ICE) vehicles, whereas further development and cost reductions of TEG devices expand their applicability at higher-power transportation means (i.e., ships and aircrafts). In this light, the integration of waste heat recovery based on TEG modules in a shipboard distribution network is studied in this work. Several voltage step-up techniques are considered, whereas the most suitable ones are assessed via the LTspice simulation platform. The design procedure of the selected LLC resonant converter is presented and analyzed in detail. Furthermore, a flexible control strategy is proposed, capable of either output voltage regulation (constant voltage) or maximum power point tracking (MPPT), according to the application demands. Finally, both simulations and experiments (on a suitable laboratory testbench) are performed. The obtained measurements indicate the high efficiency that can be achieved with the LLC converter for a wide operating area as well as the functionality and adequate performance of the control scheme in both operating conditions.

A Bi-level optimization dispatch for hybrid shipboard microgrid considering electricity-gas-heat coupling

With the increasingly severe problem of air pollution and energy crisis, new energy power generation technology in ship has quickly become the focus of attention. Compared with traditional ships, hybrid shipboard microgrid systems can achieve pollution-free, renewable and high use value. However, the integration of electricity-gas-heat in hybrid energy shipboard microgrid system also poses challenges to current optimization methods. Therefore, this paper develops a bi-level optimization dispatch model for hybrid shipboard microgrid system based on multi-objective particle swarm optimization algorithm. Taking the diesel generators, photovoltaic generation system, energy storage system (ESS) and thermal energy storage equipment into account, a hybrid shipboard microgrid system model considering electricity-gas-heat coupling is constructed. Based on this, a bi-level optimization dispatch model is established to reduce total cost, GHG (GHG) emissions and lifespan loss of ESS. The upper-level model achieves the optimization dispatch of power generation equipment and loads; a lower-level optimization model with the goal of reducing the lifespan loss of ESS is constructed. The improved multi-objective and single-objective particle swarm optimization algorithms are introduced to find the optimal dispatch solutions for bi-level optimization dispatch model. Finally, simulation results show that the proposed optimization method can not only reduce the cost and GHG emissions by 8.7% and 10.9%, but also improve the cycle life of ESS by 9.2%.

Optimal Observer-Based Power Imbalance Allocation for Frequency Regulation in Shipboard Microgrids

This paper proposes a two-level control strategy based on a super-twisting sliding-mode algorithm (STA) to optimally allocate power imbalances in shipboard microgrids (SMGs) while achieving frequency regulation. The strategy employs an STA observer to estimate the unknown power load demand imbalances in finite time. This estimate is then passed to an online high-level optimal control framework to periodically determine the optimal sequence of power reference values for each energy storage device (ESS), minimising the operational cost of the SMG. The online optimised power reference values are interpolated and passed to the low-level STA control strategy to control the output power of each ESS. The efficacy of the proposed methods is demonstrated through numerical simulations conducted on a prototypical model of an SMG equipped with two ESSs, namely batteries and fuel cells with associated hydrogen storage.

Performance Evaluation of Power Quality in Shipboard Microgrid Under Different Working Conditions

Performance Evaluation of Power Quality in Shipboard Microgrid Under Different Working Conditions

Soft variable structure fractional sliding-mode control for frequency regulation in renewable shipboard microgrids

In light of the reliable operation of renewable shipboard microgrids, this paper implements a fractional-order theory for flexible modeling for an accurate study of shipboard microgrids. Then, it introduces a novel variable structure control strategy based on a fractional-order reduced chatter nonlinear sliding mode. This strategy incorporates a time delay estimation and an optimization routine for parameter adjustments, aiming to achieve nearly time-optimal control performance and faster frequency accommodation. The proposed method exploits the benefits of fractional order modeling, reduced chatter sliding mode, and variable structure approaches. While the adapted reduced chatter strategy may decrease convergence speed, the variable structure strategy compensates for this by accelerating settling speed. These features, along with continuous, soft, and limited control signals, make the proposed method suitable for the challenging conditions of low inertia, high dynamics, uncertainty, and a noisy environment in nonlinear renewable shipboard microgrids. The Lyapunov stability proof and simulation results demonstrate the proposed method's fast, high accuracy, and reliable performance. Furthermore, the validation process, which involves comparisons with conventional sliding-mode strategies, fractional-order proportional-integral-derivative controllers, and experimental test results using the Speedgoat real-time target machine in conjunction with Simulink real-time, serves to further establish the superiority of the proposed approach.

Performance Investigation of Hybrid Shipboard Microgrid using ESOGI-FLL Technique

The issue of reducing greenhouse gas (GHG) emissions from ships has garnered significant interest from stakeholders within the maritime industry. This work considers a hybrid shipboard microgrid powered by a battery energy storage (BES), solar photovoltaic array (SPVA), and diesel generator (DG) set. The enhanced second-order generalized integrator-based frequency-locked loop (ESOGI-FLL) technique synchronizes the DG set and the shore grid at different operating modes to supply uninterruptable power to loads. The propulsion motor, nonlinear service loads, DG set, and sources equipped with power-electronic inverter result in power quality challenges within a hybrid shipboard microgrid. Thus, the ESOGI-FLL algorithm is utilized for the mitigation of power quality issues of hybrid shipboard microgrid. The hybrid microgrid is modeled in MATLAB/Simulink at different operating conditions and validated on a real-time test simulator.

Preventive-Resilient Algorithm Based on Weighted Bandwidth Method for Stable Load Management in Zonal DC Shipboard Microgrids

Preventive-Resilient Algorithm Based on Weighted Bandwidth Method for Stable Load Management in Zonal DC Shipboard Microgrids

A Novel Fault Detection and Location Approach for DC Zonal Shipboard Microgrid Based on High-Frequency Impedance Estimation With IEC 61850 Communication Protocol

A Novel Fault Detection and Location Approach for DC Zonal Shipboard Microgrid Based on High-Frequency Impedance Estimation With IEC 61850 Communication Protocol

Distributed Unified Controller Design for Parallel Battery Storage System in DC Shipboard Microgrid

In this paper, a novel distributed unified controller is designed to solve the problems of unbalanced State of Charge (SoC), unreasonable load current sharing, and unstable DC bus voltage for parallel battery storage systems (BSSs) in DC shipboard microgrid (DC-SMG). Different from the droop-based secondary controller, the designed distributed unified controller is a droop-free primary controller, which can incorporate SoC balancing, current sharing, and voltage regulation functions in the primary control layer. On this basis, each BSS uses an improved dynamic diffusion algorithm (DDA) to iteratively estimate the average information, and completes information exchange by a neighbor-to-neighbor communication network. Furthermore, the small-signal stability, large-signal stability, and global steady-state performance of the system is investigated using eigenvalue analysis, mixed potential theory (MPT), and matrix theory, respectively. Finally, the Matlab/Simulink simulation model and the StarSim HIL experimental platform for DC-SMG are built. The results show that the designed distributed unified controller can simultaneously achieve dynamic SoC balancing, proportional load current sharing, and smooth average bus voltage regulation, and has a faster SoC convergence speed and more stable control effect than the state-of-the-art methods.

A New Paradigm for Adaptive Cyber-Resilience of DC Shipboard Microgrids Using Hybrid Signal Processing with Deep Learning Method

A New Paradigm for Adaptive Cyber-Resilience of DC Shipboard Microgrids Using Hybrid Signal Processing with Deep Learning Method

DHOGI-QT2-PLL Based Control Scheme for Seamless Mode Transfer in Hybrid Shipboard Microgrid under Adverse Grid Conditions

DHOGI-QT2-PLL Based Control Scheme for Seamless Mode Transfer in Hybrid Shipboard Microgrid under Adverse Grid Conditions

Comparative study based on techno-economics analysis of different shipboard microgrid systems comprising PV/wind/fuel cell/battery/diesel generator with two battery technologies: A step toward green maritime transportation

Exploring new energy sources for maritime transportation is crucial to address the growing energy crisis and environmental pollution. Full electrified ships have the potential to bring significant economic and environmental benefits. This paper investigates the techno-economics performance such as economic, technical, and emission analyses of three different hybrid systems namely PV/wind/battery (Case I), PV/Wind/battery/Diesel generator (Case II), and PV/Wind/Fuel Cell/battery (Case III) with two different battery technologies (lead acid battery (LAB) and lithium-ion battery (LIB) technologies) for the shipboard microgrid system using HOMER Pro. A load profile of the passenger vessel "FCS Alsterwasser" was considered. Results of the economic analysis from the lead acid batteries combination revealed that Case II emerged as the most cost-effective option, with a net present cost (NPC) of $1.17 million and a levelized electricity (LCOE) cost of $0.295/kWh, while the lithium-ion battery system, Case I proved to be a most economically favorable option, demonstrated the lowest NPC at $1.12 million for and an LCOE of $0.284/kWh. On the contrary, Case I with the LAB system had the highest power production, generating 1,182,870 kWh/yr, and Case III with the LIB system produced the highest power production of 1,368,944 kWh/yr as evident from technical analysis. The emission analysis showed that Case II with the LAB system had higher emissions compared to Case III with the LIB system. The LIB system achieved higher power production and lower emissions than the LAB system. The research study is a step toward sustainable and environmentally friendly energy solutions in maritime transportation.

Hybrid ML-EMT-Based Digital Twin for Device-Level HIL Real-Time Emulation of Ship-Board Microgrid on FPGA

Maritime industries desire high speed and reliability, low lifespan cost, and environmental impact shipping for transportation. Compared to highly congested land shipments and high-cost air freight, all-electric ship (AES) can reduce the lifespan energy consumption and transport a considerable freight volume at a lower rate. Recently, the medium voltage DC (MVDC) topology, recommended by IEEE standard, pushes the AES to the next stage in considering space and weight constraints with the reduction of bulky transformers and simplified parallel connections. However, device-level modeling of this massive parallel MVDC-based ship-board microgrid (SBM) is challenging to both the state-of-the-art general-purpose compute unit and traditional electromagnetic transient (EMT) based emulation. With the rapid development of machine learning (ML) algorithm and its dedicated execution unit, accelerated parallel emulation becomes achievable in different levels of this paralleled connected SBM. Applying the ML-aided technique can help to improve the emulation execution efficiency and reduce the consumption of hardware resource on the field-programmable gate arrays (FPGAs). This work proposes a real-time hybrid ML-EMT based digital twin of the complete SBM at the subsystem-level and equipment-level with validated results from PSCAD/EMTDC <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> , and device-level with validated results from SaberRD <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> .

IEC 61850 Communication-Based Pilot Distance Protective IED for Fault Detection and Location in DC Zonal Shipboard Microgrid

IEC 61850 Communication-Based Pilot Distance Protective IED for Fault Detection and Location in DC Zonal Shipboard Microgrid

Bilevel Optimal Sizing and Operation Method of Fuel Cell/Battery Hybrid All-Electric Shipboard Microgrid

The combination of transportation electrification and clean energy in the shipping industry has been a hot topic, and related applications of hybrid all-electric ships (AESs) have emerged recently. However, it has been found that ship efficiency will be negatively impacted by improper component size and operation strategy. Therefore, the bilevel optimal sizing and operation method for the fuel cell/battery hybrid AES is proposed in this paper. This method optimizes the sizing of the AES while considering joint optimal energy management and voyage scheduling. The sizing problem is formulated at the upper level, and the joint scheduling problem is described at the lower level. Then, multiple cases are simulated to verify the effectiveness of the proposed method on a passenger ferry, and the results show that a 5.3% fuel saving and 5.2% total cost reduction can be achieved. Correspondingly, the ship’s energy efficiency is improved. This approach also can be used in similar vessels to enhance their overall performance and sustainability.

State-of-the-Art Review on Shipboard Microgrids: Architecture, Control, Management, Protection, and Future Perspectives

Shipboard microgrids (SBMGs) are becoming increasingly popular in the power industry due to their potential for reducing fossil-fuel usage and increasing power production. However, operating SBMGs poses significant challenges due to operational and environmental constraints. To address these challenges, intelligent control, management, and protection strategies are necessary to ensure safe operation under complex and uncertain conditions. This paper provides a comprehensive review of SBMGs, including their classifications, control, management, and protection, as well as the most recent research statistics in these areas. The state-of-the-art SBMG types, propulsion systems, and power system architectures are discussed, along with a comparison of recent research contributions and issues related to control, uncertainties, management, and protection in SBMGs. In addition, a bibliometric analysis is performed to examine recent trends in SBMG research. This paper concludes with a discussion of research gaps and recommendations for further investigation in the field of SBMGs, highlighting the need for more research on the optimization of SBMGs in terms of efficiency, reliability, and cost-effectiveness, as well as the development of advanced control and protection strategies to ensure safe and stable operation.