Transportation electrification is undergoing a significant transition toward the utilization of efficient and reliable energy sources and smart integration schemes, where this transitioning is continuously facing ever-tightening challenges in order to comply with the increased environmental regulations. Among the different means of transportation, global maritime transport is responsible for 2%–3% of global greenhouse gas (GHG) emissions, and it is predicted to increase to 17% by 2050 if no changes are adapted. Hence, the international maritime organization (IMO) has targeted to reach a 50% reduction in GHG emissions by 2050 compared to 2008. Hence, alternative energy sources shall be utilized in order to meet these strict GHG emissions reduction targets, where battery- and hydrogen-fed fuel cells can play a vital role in such aspects. Since the output of these two energy sources is unregulated dc voltage, their connection to the whole ship power system can be accomplished in several ways, where each way has its features, in addition to utilizing different power conditioning stages (PCSs), and these features are not well clarified and compared in the literature. Hence, this article presents an overview of the possible integration schemes that can be utilized in fuel cell- and battery-fed vessels, which is supported with a comparative assessment. This is also presented along with highlighting the state-of-the-art PCSs that are available in the market and can be utilized in these integration schemes within marine vessels. Such overview and comparative assessment are seen to be of significant importance and added value for researchers and developers in both the academic and industrial sides in order to accelerate the adoption of fuel cells in marine systems for zero-emission shipping.

This paper investigates and evaluates the performance of a single-phase split-source inverter (SSI), where an alternative unidirectional dc-ac configuration is used. Such configuration is utilized in order to use two common-cathode diodes in a single device instead of using two separate diodes, resulting in minimum parasitic inductance in the commutation paths. In this paper, the analysis and modulation of the single-phase SSI using this alternative configuration is discussed, and the analysis of the low-frequency component in the dc side is introduced. Moreover, the features behind employing the triangular, the trailing-edge sawtooth, and the leading-edge sawtooth carriers with the single-phase SSI are discussed, and the differences among these carriers are highlighted. In order to highlight the performance of the proposed SSI, a comparative study is conducted with the two-stage architecture and the single-phase quasi-Z-source inverter (qZSI). The introduced analysis is enhanced with simulation results using MATLAB/PLECS models, where a 1-kVA single-phase SSI is designed and simulated. Finally, the designed 1-kVA single-phase SSI is implemented experimentally and tested at different operating points, i.e., at different voltage gains, and a maximum efficiency of 95.5% is obtained.

Several single-stage topologies have been introduced since kicking off the three-phase Z-source inverter (ZSI), and among these topologies, the quasi-ZSI (qZSI) is the most common one due to its simple structure and continuous input current. Furthermore, different modulation strategies, utilizing multiple reference signals, have been developed as well. However, prior art modulation methods have some demerits, such as the complexity of generating the gate signals, the increased number of switch commutations with continuous commutation at high current level during the entire fundamental cycle, and the multiple commutations at a time. Hence, this paper proposes two modified space vector modulation strategies, aimed at the reduction of the qZSI number of switch commutations at high current level for shorter periods during the fundamental cycle, i.e., reducing the switching loss, simplifying the generation of the gate signals by utilizing only three reference signals, and achieving a single-switch commutation at a time. These modulation strategies are analyzed and compared to the conventional ones, where a reduced-scale 1-kVA three-phase qZSI is designed and simulated using these different modulation strategies. Finally, the 1-kVA three-phase qZSI is implemented experimentally to validate the performance of the proposed modulation strategies and verify the reported analysis.

Impedance source inverters have experienced a fast evolution since the first release of the Z-source inverter in 2003. This evolution is not limited to improving the structure of the different topologies but also includes their modulation and control schemes in order to reinforce their performance from many perspectives. Accordingly, many modulation schemes have been proposed in different research activities, but the full differences among these modulation schemes, including their effect on the switching losses, are not clear yet to the researchers. Hence, this research activity is aimed at introducing a comprehensive review of these different modulation schemes employed for the three-phase impedance source inverters, which is enhanced with a comparative assessment. In this paper, different modulation schemes are classified and reviewed, introducing an important benchmark in order to identify the basic differences between these modulation schemes. In other words, from this paper, the concept of classifying the different modulation schemes and the mandatory equations to implement each scheme can easily be drawn. Moreover, this review is essential for the next part, i.e., Part II, in which a comparative assessment is introduced.

The all-electric ship (AES) with DC-grid configuration has demonstrated advantages compared to the traditional AC system and has become the state-of-the-art for ships with electric propulsion in the low to medium power range during the past decade. However, the integration with different power sources, such as fuel cells, batteries and diesel gen-sets, increases the system complexity and requires an advanced power management system (PMS) to handle vessel operation and to achieve optimal power control. This paper presents an optimized power management strategy to reduce the total cost of ownership of such vessels, considering not only the fuel cost and emission penalty, but also the power device degradation and equipment replacement cost. In this study, Model Predictive Control (MPC) and Reinforcement Learning (RL)-based PMS control methods are approached respectively. In order to demonstrate the performance of MPC and RL techniques, a typical tugboat load profile is simulated. The testing results are also compared with a traditional rule-based power management control.

This paper proposes a modified coupled-inductor SEPIC dc-dc converter for high voltage gain (2 < G < 10) applications. It utilizes the same components as the conventional SEPIC converter with an additional diode. The voltage stress on the switch is minimal, which helps the designer to select a low voltage and low RDS-on MOSFET, resulting in a reduction of cost, conduction and turn ON losses of the switch. Compared to equivalent topologies with similar voltage gain expression, the proposed topology uses lower component-count to achieve the same or even higher voltage gain. This helps to design a very compact and lightweight converter with higher power density and reliability. Operating performance, steady-state analysis and mathematical derivations of the proposed dc-dc converter have been demonstrated in the paper. Moreover, extension of the circuit for higher gain (G>10) application is also introduced and discussed. Finally, the main features of the proposed converter have been verified through simulation and experimental results of a 400 W laboratory prototype. The efficiency is almost flat over a wide range of load with the highest measured efficiency of 96.2%, and the full-load efficiency is 95.2% at a voltage gain of 10.