A surface-mounted permanent magnet synchronous motor (SPMSM) is an electric motor with a simple magnetic circuit design, fast responsiveness, linear torque–current characteristics, speed–voltage characteristics, and constant operating speed. SPMSMs use only magnetic torque; however, interior PMSMs (IPMSMs) have high power densities because they can use reluctance torque. In addition, when flux-weakening control is used, the operating range is wide compared with the SPMSM. This study presents a comparative analysis of the characteristics of SPMSM and bar-type IPMSM. Characteristic analyses are performed by setting the same stator shape, rated speed, number of turns, winding specifications, voltage limit, and magnet usage in a pole/slot combination of six poles and 27 slots. Next, we compare the no-load back electromotive force, cogging torque, and loss characteristics, and perform a characteristic analysis of each model while satisfying the design specifications. No-load and load tests are performed using a back-to-back system. The results of the analysis and experimental results are in good agreement, and the reliability of the analysis results is guaranteed. The SPMSM is approximately 8.5% superior to the IPMSM in terms of core loss, and the eddy current loss is greater than that of the IPMSM.

In general, permanent magnet (PM) motors are driven by a pulse width modulation (PWM) voltage source inverter for vector control. The generated PWM signals cause high-frequency voltage components at the carrier frequency. Such components can increase the electromagnetic losses, thereby necessitating the consideration of the phase current corresponding to the carrier harmonics. This study aims to examine the feasibility of high-speed permanent magnet (PM) motors in which rare-earth magnets are replaced by ferrite magnets, by considering the current harmonics. The electromagnetic characteristics of a high-speed motor with rare-earth and ferrite PMs were analyzed considering the current harmonics. Based on the existing rare-earth magnet model, a ferrite magnet model with the same performance was developed to perform a comparative analysis. The findings were validated via comparison with the experimental results of the manufactured models.

This study deals with the analysis of electro-mechanical characteristic analysis on permanent magnet synchronous machines (PMSMs) for electrically driven tools primarily used in industrial applications. This study compares the noise, vibration, and harshness (NVH) characteristic results generated by fractional pole/slot combinations. The electromagnetic (EM) analysis results of the PMSMs are derived using the finite element method (FEM), and the NVH analysis is performed by applying the EM analysis results. The analysis results and the effects of EM characteristics on the vibration of the PMSMs were analyzed. The effects of EM excitation characteristics on the rotor vibrations in the PMSM were compared and analyzed.

Rotor eccentricity occurs during manufacturing, causing the de-vice to vibrate and make noise, thereby shortening its life. Its characteristics can be analyzed via the existing finite element method (FEM); however, analyzing characteristics according to design variables is time-consuming. Therefore, we implemented an analytical method that can rapidly identify the characteristics according to the design variables. We derived the magnetic flux density, the back-electromotive force, and the torque through the analytical method according to rotor eccentricity. The rotor eccen-tricity was considered to be based on the perturbation and the electromagnetic theories; accordingly, the governing equations and boundary conditions were derived. The analytical method was validated through FEM and experimental result.

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.

In this study, to analyze the effects of electromagnetic factors that are affected by the eccentricity on vibration, an overall structural model of a motor was constructed, including the stator core, rotor structure, and the other parts. Thereafter, a mode analysis was performed to verify the dynamic stiffness of the constructed model using the finite element method. Vibration analysis was performed using a method that applied the electromagnetic characteristic analysis results to the mechanical system using the finite element model of the entire mechanical system, and the analysis results were obtained. To verify the validity of the proposed analysis method, a comparison of the test results obtained from the finite element analysis and fabrication model was performed. Finally, by analyzing the effect of changes in the electromagnetic characteristics due to eccentricity on vibration, it was confirmed that the change in electromagnetic characteristics was reflected in the vibration characteristics. In addition, the trend followed by the vibration characteristics derived from the analysis results agreed well with the measured vibration tendency, indicating that the vibration analysis could be performed by the method presented in this paper.