In this paper, the optimal design of a brushless direct current motor with a three-dimensional (3D) structure using the response surface methodology (RSM) is presented. There were two optimization goals: reduction of the cogging torque and maintenance of the back electromotive force to prevent performance degradation. For motors with a 3D structure, a 3D finite element method analysis is essential, though it requires considerable computation time. Therefore, to reduce the optimal design time, the 3D structure was placed on the 2D plane. Thereafter, a 2D corrected model was applied to the RSM. For the validity of the technique, the analysis results of the initial 3D model, 2D model, and 2D corrected model were compared, and the results of the optimal design 3D model, 2D corrected model, and experiment were compared.

Permanent magnet (PM)-type linear oscillating actuators (LOAs) are used in various types of equipment owing to their high efficiency, thrust density, and good control performance. However, the disadvantage of the LOA is the side force inevitably generated by the magnetic coupling structure of the stator and the PM mover. Therefore, side force reduction is essential at the design stage. This study manages the optimal side force design of a movable PM-type linear actuator using response surface methodology (RSM). Based on the Maxwell stress equation, three optimization variables were selected for the magnet shape, and experimental points were selected using the Box–Behnken design. The RSM was performed based on the results of the experimental points obtained through the finite element method. To prevent output reduction, the back electromotive force, which is directly proportional to the thrust, was selected as the constraint. The validity of the optimal design was verified through a characteristic comparison between the optimal and initial models along with experimental verification.

This paper proposes 2D equivalent analysis techniques for BLDC motors with 3D structures that are permanent magnet (PM) overhang and housing-integrated rotor core. These 3D structures require 3D analysis method for accuracy of analysis. However, being a time consuming process, 3D analysis method is not a suitable choice for initial motor design. In this paper, it is proposed that this limitation can be addressed by replacing 3D structures with 2D equivalent analysis techniques. First, PM overhang is corrected to have same magnetic energy as in 2D analysis model. Second, housing-integrated rotor core is corrected to consider magnetic flux in radial direction. Finally, the 2D equivalent analysis techniques is validated by comparing experimental results of electromagnetic performance with corrected and uncorrected 2D analysis models.

This study presents an approach to calculating the temperature increase in the internal components of permanent magnet synchronous machines by applying lumped-parameter thermal networks and analytical methods. Accordingly, the thermal equivalent circuit method is employed to obtain the temperatures of the machine’s internal components. Furthermore, this analytical method predicts the temperature distribution in the slot area. The 24/6 prototype was used to evaluate the proposed model by comparing the calculated and finite element method simulation.

This study proposes an innovative approach that integrates the subdomain method with sequential quadratic programming (SQP) to optimize the volume of a high-speed surface-mounted permanent magnet synchronous motor in an air compressor operating at 110 000 rpm. Unlike conventional optimization tools that often rely on finite element analysis (FEA) software, by leveraging the subdomain method for electromagnetic modeling, we obtain an analytical solution that rapidly represents the behaviors of the motor. Subsequently, the SQP technique is applied to optimize the volume of the model while satisfying design constraints. The proposed model is verified by FEA simulation.

In this study, we performed an electromagnetic characteristic analysis of a permanent magnet synchronous machine considering the current waveform based on static rotor eccentricity. First, the characteristics of the back electromotive force were analyzed through the no-load analysis of the analysis model according to static rotor eccentricity. Next, a dynamic analysis was performed through mathematical modeling of a permanent magnet synchronous motor and PWM method. The input current during operation was derived through the dynamic analysis, and the core loss analysis was performed using derived input current. The core loss analysis was performed using the case where the fundamental wave current was applied and the input current derived through the dynamic analysis, and the results were compared.