The concept of a Removable-Battery Powered Fully Electric Ship (RBP-FES) addresses challenges such as high investment and maintenance costs of large batteries. As the primary energy consumer in an electric ship system, the propulsion motor must be designed to meet the requirements of various propulsion system components, ensuring high efficiency. Permanent Magnet Synchronous Motors (PMSMs) are favored due to their high efficiency, power density, and compact size. However, PMSMs exhibit temperature-dependent performance, requiring simultaneous consideration of electromagnetic and thermal aspects. This study presents a system-level design and coupled electromagnetic-thermal analysis of a 500 kW Interior Permanent Magnet Synchronous Motor (IPMSM) for RBP-FES applications. The design process includes load design (hull, propeller, and gear) and explores the relationship between the C-rate levels of the battery system and the propulsion motor in determining initial physical parameters. A coupled analysis integrating electromagnetic Finite Element Analysis (FEA) and thermal networks is developed, and its results are discussed. The prototype is built and tested to validate the design and analysis outcomes. The experimental results show that the IPMSM reached an efficiency of 98.3% at rated power. Furthermore, the temperature rise test results match well with coupled analysis, with a deviation of less than 2°C.

The Korean government is facing growing concern over the increasing levels of fine dust. A significant contribution to this problem comes from coastal vessels. To mitigate this, an electric ship propulsion system has been proposed as a solution to reduce air pollution. The application of a fully electric propulsion system in a ship is challenging due to size, capacity limitations, and the cost investment of the battery system. To address the challenges of battery limitation and initial investment costs, the development and supply of removable battery supply systems (RBSSs) for fully electrified battery powered (F-EBP) car ferries are studied. A permanent magnet synchronous motor (PMSM) for the F-EBP car ferry using a roll-on/roll-off-type RBSS is developed in this work. Firstly, the concept of the F-EBP car ferry is discussed, and the specifications of the electric car ferry propulsion system are provided. Secondly, motor design and electromagnetic analysis are performed using finite-element analysis (FEA), where the heat sources including copper loss, core loss, and PM loss are calculated. Mechanical loss is also considered. Finally, a thermal network of the motor is built considering the lumped-parameter model. The results of the thermal analysis indicate that the motor operates within the safe region and can perform well in rated working conditions.

Based on the shock absorber size and power and power density limitations in motorcycle application, a linear permanent magnet machine for a regenerative suspension system that recovers the kinetic energy originating from shock absorber vibration is investigated. To achieve the target power of 120 W, several design parameters were investigated. The eight-slot eight-pole combination was used due to its high power density. A hybrid permanent magnet structure was implemented which was a combination of a classical Halbach array and iron spacers. In addition, the dimensions of the permanent magnet, and stator inner radius were parametrically studied to enhance the air-gap flux density and coil volume, which are the main factors affecting performance. The detailed design generated 124 W of average power under the rated condition, assuming a vibration speed of 0.157 m/s. Despite the satisfaction of the output power and power density, the large magnetic force caused by the interaction between the iron core and permanent magnet is the main drawback of this design, which has a negative impact on driving safety and comfort. To commercialize the suggested device, additional studies will focus on size, electromagnetic reduction, as well as road test performance.

The increasing demand for lightweight, high-efficiency electrical machines has driven research into copper-carbon nanotube (Cu-CNT) composites as alternatives to copper windings. While Cu-CNT-based conductors show promise, their bi-directional electromagnetic-thermal behavior in permanent magnet synchronous generators (PMSGs) remains underexplored. This study evaluated the feasibility of Cu-CNT windings to enhance power density, thermal management, and efficiency through a coupled analysis using 2D electromagnetic finite element analysis integrated with a lumped parameter thermal network. Two Cu-CNT materials with a resistivity of $7.12\times 10^{-8}~\Omega $ .m (Cu-CNT #1) and $2.12\times 10^{-8}~\Omega $ .m (Cu-CNT #2) were tested over speeds ranging from 1000 to 4800 RPM with parametric variations in axial length and outer diameter. Results show that Cu-CNT #2 delivered higher specific power and, at high temperatures, achieved better efficiency than the copper-based model. Due to limited composite material samples from current processing and manufacturing, a copper coil prototype was manufactured for validation. The good agreement between the simulation and the test results of the copper-based confirms the accuracy of the coupled electromagnetic-thermal analysis. As a result, the correctness of the Cu-CNT-based model is validated.

This study proposes a computationally efficient torque estimation model for the Interior Permanent Magnet Synchronous Motor (IPMSM), considering the temperature-dependent magnetic properties of the permanent magnet (PM). It is well known that the magnetic flux of the IPMSM is caused by both the PM and the current source in the stator winding. Hence, the magnetic torque depends on PM temperature as PM flux varies with temperature variation. Using finite element analysis (FEA), the proposed model accounts for nonlinear characteristics such as d,q cross-coupling, and saturation effects based on flux linkage mapping. Moreover, static FEA is conducted to achieve time-efficient computation, and the least number of required simulations is considered. An IPMSM designed for the target high-speed train traction motor is employed to validate the proposed method. Validation is conducted by comparing the results obtained from the proposed prediction model with results from time-transient FEA at different PM temperatures. The results show a good agreement between the proposed method and the FEA results while significant reduction simulation time.