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The energy transition and the decarbonization of transport dictate a switch towards electrification in the naval sector. Ferries, among the different types of ships, are those most suited for a full electrification, consisting in the replacement of engines with electric motor drives and fuel tanks with electrochemical energy storage systems. However, some cost issues and energy storage technological limitations still hamper full electrification, making partial electrification more practical, which can still be effective in reducing pollutant emissions in ports and surrounding areas. The aim of this work is to investigate some issues related to onboard energy storage systems needed for electric ferries. The Ro-Ro Elio ferry, operating in the Strait of Messina is considered as a case study. Some different solutions are investigated, in terms of economic/enviromental efficiency, which is the cost of preventing the emission of a kg of CO2.

The electrification of ferries requires efficient shore infrastructures that include energy supply grids, communication networks, charging systems, energy storage systems, interfacing and monitoring devices. In this context, a lot of research and development efforts have been made in the last decade that are reviewed in this paper. Energy storage technologies, battery charging requirements and their safety parameters are first analyzed. A comprehensive review on shore side infrastructure design and power system architecture are then provided. Different shore to ship interfaces are finally presented along with, some alternative solutions to battery charging stations.

A multi-level open-end winding converter topology for multiple-motor drives is presented featuring a main multi-level inverter processing the power delivered to the motors and an active filter based on an auxiliary two-level inverter. The main inverter operates at the fundamental frequency in order to achieve low switching power losses, while the active filter is Pulse Width Modulation (PWM) operated to suitably shape the motor currents. The proposed configuration features less phase current distortion than conventional multi-level inverters operating at the fundamental frequency, while achieving a higher efficiency compared to PWM multi-level inverters. Experimental results confirm the effectiveness of such a configuration on both multiple motors-single converter and multiple motor-multiple converter drives.

The paper presents a self-sensing control technique for a special type of multilevel motor drive featuring an Open-end Winding Permanent-Magnet Synchronous Motor fed on one side by a main multilevel inverter (MLI) and on the other side by an auxiliary two-level inverter (TLI). In order to minimize the power losses, the MLI manages the machine active power operating at a low-switching frequency. The TLI instead acts as an active power filter and operates at a higher switching frequency and a lower DC-Bus voltage than the MLI. The current control task is shared between the two inverters, as a predictive action is exerted by the MLI, while a feedback action is accomplished by the TLI. Common sensorless rotor position estimation techniques cannot be straightforwardly applied on such a system, due to the particular drive structure. Therefore, a specific technique has been carried out, able to ensure satisfactory efficiency and control performance in all the operating speed ranges by optimally exploiting the different features of the two inverters. Simulation and experimental results confirm the effectiveness of the proposed approach.

The paper deals with a fuzzy logic based strategy managing the power flows in an hybrid generation plant. Such a plant works in island mode and is composed of: a wind turbine, a photovoltaic generator and a fuel cell/electrolyzer energy storage system. The performances of the proposed strategy are evaluated by simulation in different operating conditions. To this purpose some performance indexes are considered, such as: the frequency deviation, the stability of the DC bus voltage and the AC voltage total harmonic distortion. Simulation results confirm the effectiveness of the proposed power management strategy, providing the ground for the practical realization of a fuzzy logic based control system. Moreover the efficiency of the developed fuzzy logic controller is compared to that of a more conventional controller taking into the fuel cell H 2 consumption, the amount of H 2 generated from the Electrolyzer and the final battery state of charge (SOC).

A three-phase multi-level multi-input power converter topology is presented for grid-connected applications. It encompasses a three-phase transformer that is operated on the primary side in an open-end winding configuration. Thus, the primary winding is supplied on one side by a three-phase N-level neutral point clamped inverter and, on the other side, by an auxiliary two-level inverter. A key feature of the proposed approach is that the N-level inverter is able to perform independent management of N − 1 input power sources, thus avoiding the need for additional dc/dc power converters in hybrid multi-source systems. Moreover, it can manage an energy storage system connected to the dc-bus of the two-level inverter. The N-level inverter operates at a low switching frequency and can be equipped with very low on-state voltage drop Insulated-Gate Bipolar Transistor (IGBT) devices, while the auxiliary inverter is instead operated at low voltage according to a conventional high-frequency two-level Pulse Width Modulation (PWM) technique and can be equipped with very low on-state resistance Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) devices. Simulations and experimental results confirm the effectiveness of the proposed approach and its good performance in terms of grid current harmonic content and overall efficiency.

Capacity loss over time is a critical issue for lithium-ion batteries powering battery electric vehicles (BEVs) because it affects vehicle range and performance. Driving cycles have a major impact on the ageing of these devices because they are subjected to high stresses in certain uses that cause degradation phenomena directly related to vehicle use. Calendar capacity also impacts the battery pack for most of its lifetime with a capacity degradation. The manuscript describes experimental tests on a lithium-ion battery for electric vehicles with up to 10% capacity loss in the WLTP CLASS 3B driving cycle. The lithium-ion battery considered consists of an LMO-NMC cathode and a graphite anode with a capacity of 63 Ah for automotive applications. An internal impedance variation was observed compared to the typical full charge/discharge profile. Incremental capacitance (IC) and differential voltage (DV) analysis were performed in different states of cell health. A lifetime model is described to compute the total capacity loss for cycling and calendar ageing exploiting real data under some different scenarios of vehicle usage.