Design of a Permanent Magnet Synchronous Motor for Rim-Driven Electric Propulsion Ship Powertrain

Stricter environmental regulations by the International Maritime Organization (IMO) have increased the demand for high-efficiency and eco-friendly marine propulsion systems. Rim-driven thrusters (RDTs), which integrate the motor rotor with the propeller, offer advantages such as reduced mechanical losses, low noise, and improved maneuverability compared to conventional shaft-driven systems. This study investigates the feasibility of a 1.5 MW-class bearingless rim-driven propulsion motor by designing a 30 kW scaled permanent magnet synchronous motor (PMSM) for experimental validation. The motor is developed under volume constraints while meeting voltage, torque, and speed requirements, considering the large air gap of bearingless structures. Pole-slot combinations are selected and optimized to minimize torque ripple and cogging torque. Electromagnetic analysis verifies performance and confirms the feasibility of the proposed design for high-efficiency marine propulsion applications.