Advancements in electrical marine propulsion technologies: A comprehensive overview

The shipping industry is shifting towards efficient and environmentally friendly propulsion systems to reduce costs and ecological impact. Traditional diesel engines, predominant in maritime operations, face challenges of high operating costs and environmental pollution, prompting the exploration of alternatives. Electric propulsion emerges as a promising solution, offering cost reduction and environmental preservation through reduced noise, This paper reviews electric ship propulsion systems and compares various marine propulsion systems, including in-hull, azimuth, and POD propulsion, with an emphasis on the latest POD systems. Specifically, it analyzes AZIPOD (ABB) and Mermaid (Rolls-Royce) propulsion systems in terms of motor type, cooling system, and power range. Additionally, the paper provides insights into the electrical components of POD propulsion, and the latest technology in ship propulsion, such as transformers, frequency converters, and propulsion motors, and explores redundancy in ship propulsion systems. It offers a detailed comparison of different electric motors, including DC motors, induction motors, superconducting motors, synchronous motors, and permanent magnet motors, discussing the advantages and disadvantages of each. This comprehensive review underscores the potential of electric propulsion systems to transform the maritime industry toward sustainability and efficiency.