Integrated Power and Energy Systems (IPESs) will play a critical role in supporting future complex electric ship operations. In particular, flexibility is required to exploit shipboard energy sources and storages for multiple ship functions, supporting a highly dynamic electrical power use. To this aim, the Medium Voltage DC (MVDC) electrical power distribution has been conceived to provide requested power flexibility, along with other expected advantages in terms of functional integration and ship design. For complex and high-performance ship power systems, the Zonal Electrical Distribution System (ZEDS) concept has been proposed to maximize MVDC capabilities even under extremely demanding operational conditions. This paper presents a megawatt-scale test facility of a MVDC ZEDS developed and built in Trieste, Italy, based on power electronics open system interfaces. The demonstrator is described in its power and control design architectures and capabilities. In particular, a successful MW-scale test is presented, to show ZEDS capability in supporting large and fast load variations, while maintaining acceptable MVDC voltage tolerances.

Incorporation of energy storage directly into the distribution system of a Navy ship can enable new dynamic high-power loads and improve overall energy efficiency. This paper investigates the integration of energy storage onboard an all-electric destroyer by designing a solution for an advanced combination of loads and establishing a procedure for incorporating energy storage directly into the distribution system design. A case study is examined in which a battery is sized for a defined load and integrated into a ship design with associated peripherals. The selected battery is simulated to verify expected performance. The study investigates a battery-based system that provides peak shaving to assist the traditional generation system in supplying pulsed and stochastic loads, while also enabling single-generator operations. Such an energy storage system provides notable benefits in terms of fuel consumption during normal operations while also guaranteeing a stable and continuous power supply to the mission loads during battle scenarios.

The most advanced DC shipboard power systems will be based on the wide deployment of controlled converters in a zonal distribution configuration. On one side the power electronics arrangement enables advantages for the onboard functioning (e.g. flexibility, redundancy and adaptability), on the other it can open worrying issues on DC system stability. When perturbing a negative-damped DC power grid, the incoming instability triggers a ship blackout as a consequence. To avoid this catastrophic eventuality, the Power Management System (PMS) is programmed for the smart real-time adaptation of converters bandwidths. The paper presents a Preventive-Resilient (P-R) bandwidths tuning to guarantee the stable functioning, even when assuming the (n-1) eventuality, so the unexpected disconnection of the more stabilizing load. This reconfiguration is an effective measure to constantly ensure a sufficient stability margin, even when low-bandwidth loads are offline. The capability of P-R algorithm is evaluated by a C-HIL test on a digital real-time platform. A Python code acts as a PMS in configuring the bandwidths on emulated converters via the Modbus communication protocol. The combination of a simplified stability assessment method with an optimization algorithm enables a fast bandwidth reconfiguration process without requiring excessive computational effort. These characteristics make the proposed approach suitable for integration into the shipboard Power Management System (PMS), providing central controllers with an online stability assessment and safe load management tool.

Nowadays, the industrial world is undergoing a disruptive transformation towards more environmentally sustainable solutions. In the blue economy, this new approach is not only expressed in the domain of actual vessels, but also in the development of charging infrastructure, displaying a notable transition towards more eco-friendly solutions. The key focus lies in adopting flexible power systems capable of integrating renewable energy sources and storage technologies. Such systems play a crucial role in enabling a shift towards low-emission maritime transport. The emissions reduction goal extends beyond onboard shipboard distribution systems, encompassing also the design of supplying platforms and marinas. This study explores the implementation of a controlled DC microgrid tailored to efficient management of power flows within a yacht marina. Once having established the interfaces for the vessels at berth, the integration between the vessels, the onshore photovoltaic plant and the battery storage unit is made possible thanks to the coordinated management of multiple power converters. The overarching goal is to curtail reliance on external energy sources. Within this DC microgrid framework, a centralized controller assumes a pivotal role in orchestrating the power sources and loads. This coordinated management is essential to achieve sustainable operations, ultimately leading to the reduction of emissions from both ships and onshore power plants.

Nowadays, the energy storage solutions are reaching a more prominent role when integrated in DC shipboard power systems. Among others, batteries and supercapacitors are already capable of assisting the traditional on-board energy resources, both during normal operation (e.g. fuel consumption optimization, peak shaving, pulsed loads supply) and in critical situations. When a main source of energy goes out of service, the remaining online sources and the storage are to be proficiently managed, thus ensuring enough power to the vital loads without outages. In this scenario, the power sharing between the storage systems gets a notable importance, as an accurate load subdivision can actually extend the power-on time. The paper investigates different options to manage the Battery Energy Storage Systems of a DC shipboard power system. Two batteries are onboard installed to temporarily support the loads supply if a generating system disconnection occurs. Three power sharing profiles are investigated to identify the best solution in preserving the State of Charge of batteries.

The paper proposes the implementation of a controlled DC microgrid to supply DC loads in a plating industry. The plating loads, typically from chromium-based surface coating processes, are characterized by low voltage (10-20 V) and high currents (5-10 kA). To adopt renewable sources, the supplying 600 V-DC microgrid is powered by a photovoltaic (PV) system and a Battery Energy Storage (BES) system. Main aim of the work is to develop a smart strategy to reduce energy consumption, while lowering electricity costs, and minimizing the current ripple affecting the loads. Since PV systems cannot provide a continuous power supply, the system also includes an interface with the external AC grid by a bidirectional DC/AC converter. This hybrid converter allows to feed back the PV energy excess to the grid, still ensuring electricity supply when needed. The paper wants to provide a technical-economic overview, from the sizing of PV and BES systems to the voltage control system, including an Energy Management System (EMS). In particular, the study is aimed at determining the optimal PV system size and BES capacity size to maximize the Net Present Value (NPV) of investments-originated savings. Industrial electricity load profiles, PV generation data derived from 18 years of average hourly irradiation, and three years of electricity price profiles are adopted as optimization inputs. Particularly, the BES power is optimized over a one-year period to minimize grid energy exchange, with annual cost curves to maximize the NPV. Finally, with the same MILP approach as sizing, an EMS with real-time control is proposed in the optimization of microgrid devices, while the DC voltage control system is discussed in detail with tests performed on a Hardware In the Loop (HIL) platform in some scenarios among equilibrium conditions. The paper aims to make a contribution to the development of energy management strategies for reducing procurement costs in industries that make extensive use of DC current, suggesting the entire process, from the optimal calculation of the sizing of the components, to the daily management of the microgrid with optimized scheduling of the EMS, including the control system.