Slotless-type motors have a very constant torque without cogging torque because the windings are arranged in the gap of the stator. In addition, since there is no stator teeth structure, reduces harmonic generation, and the eddy current loss of the permanent magnet and iron loss are small, resulting in high efficiency. However, slotless motors generate large current harmonics due to their low inductance when pulsewidth modulation (PWM) control is considered. Large current harmonics affect torque ripple and voltage THD, resulting in reduced motor performance. Therefore, additional inductance is required for slotless motors. In this article, the process for the detailed design of slotless-type motors and determining the inductance through PWM analysis is proposed. A detailed design technique for a slotless motor that satisfies the target performance and limitations was presented. In addition, PWM control was implemented using MATLAB’s Simulink to determine the accurate inductance. The validity of the proposed process is verified by finite element analysis (FEM) using PWM control.

Duct fan motors must provide high torque within limited space to maintain airflow while requiring low vibration characteristics to minimize fluid resistance caused by fan oscillation. Axial Flux Permanent Magnet Motor (AFPM) offers higher torque performance than Radial Flux Permanent Magnet Motor (RFPM) due to their large radial and short axial dimensions. In particular, the coreless AFPM structure enables superior low-vibration performance. Conventional AFPM typically employs a core-type stator, which presents manufacturing difficulties. In core-type AFPM, applying a multi-stator configuration linearly increases winding takt time in proportion to the number of stators. Conversely, a Printed Circuit Board (PCB) stator AFPM significantly reduces stator production time, making it favorable for implementing multi-stator topologies. The use of multi-stator structures enables various topological configurations depending on (1) stator placement, (2) magnetization pattern of permanent magnets, and (3) rotor arrangement—each offering specific advantages. This study evaluates and analyzes the performance of different topologies based on efficient arrangements of magnets and stators, aiming to identify the optimal structure for duct fan applications. The validity of the proposed approach and design was verified through three-dimensional finite element analysis (FEA).

In this paper, a high-power hybrid electric motor is proposed in which 3DP technique is applied to the fabrication process to improve the power density of the motor. energy saving and environmental issues have become a global issue, research on increasing power density to simplify the system while reducing the resources consumed in manufacturing has become important in recent years. To improve power density, research is being conducted on optimizing various design parameters. However, in the case of motors manufactured by the general mold pressing process, a pressing process is used to press metal sheets into a mold of the desired shape with a strong force, but due to the limitations of the process itself, the shape design is limited and the design parameters for improving power density are also limited. Therefore, this paper applies 3DP technology to secure the shape freedom of the motor and proposes a hybrid motor design process to improve the output density. Among the 3DP production methods, the SLM method is adopted, and the SLM technique has the advantage of securing high strength and mechanical precision, and it is advantageous for design because it can freely manufacture objects with complex shapes. The hybrid motor is a structure that combines a radial type of permanent magnet motor and an axial type of permanent magnet motor based on the design freedom secured through the 3D printing process, and the shape was optimized to satisfy a higher output density than the general basic model.

In this paper, a single-phase BLDC motor is applied to a cooling fan motor and a Drive IC integration analysis method of the single-phase BLDC motor is proposed. Single-phase BLDC motors have a simple structure, are easy to manufacture, and are low cost, so they are used in applications where low outputs and low costs are advantageous. Single-phase BLDC motors use a full-bridge inverter (Drive IC), and this inverter (Drive IC) has dead time due to switching. Therefore, in order to consider dead time when analyzing a single-phase BLDC motor, analysis through integration with Drive IC is necessary. This paper compares the types of single-phase BLDC motors, designs a model that satisfies target performance, and conducts research on Drive IC integration analysis through FEA. A prototype motor was manufactured and tested, and the validity of the Drive IC integration analysis was verified.

The claw-pole motor, known for its simple structure, is widely used in various fields due to its cost competitiveness. However, a drawback of the fixed-stator-type claw-pole motor is its vulnerability to eddy current losses. Therefore, this paper presents a single-phase claw-pole motor applied as a motor for cooling fans, with the aim of reducing eddy current losses and improving performance based on shape optimization, ultimately resulting in a single-phase claw-pole motor that meets the desired performance. The validity of this approach is verified through 3D finite element analysis (FEA).

In recent electrification applications, including automotive drive systems, the demand for high-power-density permanent magnet motors capable of delivering high torque and power within a limited volume has been increasing. In this paper, a hybrid-type permanent magnet synchronous motor (H-PMSM), which can simultaneously utilize the advantages of a radial flux motor (RFM) and an axial flux motor (AFM), is proposed, and an outer-rotor structure is adopted to improve winding manufacturability and the slot fill factor. The proposed outer-rotor H-PMSM is configured with the AFM in the upper part and the RFM in the lower part, and the two parts are connected by a single winding so that the conventional end-turn region can act as an additional effective conductor. In addition, by adopting the outer-rotor structure, the ease of the winding process is improved and a high slot fill factor can be achieved. The proposed structure was analyzed by finite element analysis (FEA), and it was confirmed that the total torque was greater than the simple sum of the torques generated by the AFM part and the RFM part, indicating the possibility of an additional torque contribution from the end turn. In addition, a prototype motor was fabricated, and it was confirmed that the slot fill factor of the outer-rotor structure was improved to approximately 40% compared with that of the inner-rotor structure. It was also confirmed that the FEA results agreed well with the prototype results in terms of performance, thereby validating the proposed outer-rotor H-PMSM.