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 this article, an exact analytical model for predicting irreversible demagnetization in Permanent Magnet Synchronous Machines (PMSMs) under overload and high-temperature conditions is presented. The proposed model includes a nonlinear model combined with a process for determining demagnetization. First, the nonlinear model considers non-uniform magnetization by dividing each permanent magnet (PM) into numerous small segments with separated remanence flux densities (RFDs). Harmonic modeling (HM), combined with an iterative loop, is employed to obtain nonlinear solutions, accurately capturing saturation effects that lead to high demagnetizing fields. The RFDs are iteratively updated until convergence is achieved. The proposed model can accurately predict machine behavior, capturing both demagnetization and saturation effects. Validation using a PMSM shows excellent agreement with both Finite Element Analysis (FEA) and experimental results, significantly reducing computation time compared to FEA simulations. This approach provides a robust tool for engineers to design and evaluate PMSMs, ensuring machine reliability under adverse conditions.

Permanent magnet synchronous machines (PMSMs) with an overhang structure can increase power density by compensating for the increased magnetic energy of permanent magnets. To analyze the overhang structure, a three-dimensional (3D) analysis of PMSMs is essential. However, 3D analysis takes a long time and the modeling process is complicated in the initial design stage. To overcome these problems, a magnetic equivalent circuit technique is applied to the 2D model. In this paper, an optimal design method for PMSMs with an overhang structure is proposed based on the semi 3D magnetic equivalent circuit (MEC) and random walk method. By using semi 3D MEC, it is possible to quickly analyze PMSM and obtain accurate electromagnetic analysis results considering the overhang effect. Moreover, the volume and weight of PMSM can be minimized by optimizing the rotor’s four design parameters using a random walk algorithm. To obtain high efficiency, the objective function is selected so that copper loss is minimized under the same constraints. The validity of the proposed design technique is verified by comparing the analysis results of semi 3D MEC and 3D finite element method for the derived optimal model.

This study presents an approach for calculating the stress and deformation increase in the modulation of magnetically geared machines using a mathematical method. An analytical method is employed to obtain the magnetic force density acting on the modulation components. Afterward, the proposed mathematical method predicts the mechanical characteristics. The 9 slots/32 poles/19 modulations model was evaluated via a comparison with the finite element method simulation.

This study presents an approach to optimizing the output power in a magnetically geared generator by employing subdomain modeling and particle swarm optimization. Accordingly, the subdomain analytical method is utilized to obtain the induced voltage, inductance which are used to predict output power. Afterward, the swarm intelligence optimization technique is applied to reach the maximum output power point. The 12/17/15 prototype evaluated the proposed model by comparing the calculated results and finite element method simulation.

This paper presents both analytical calculations and empirical measurements of the magnetic force between the permanent magnet (PM) and rotor yoke in a large-scale permanent magnet synchronous generator (PMSG). The assembly of PMs in large-scale PMSGs is particularly challenging owing to the substantial magnetic forces involved. Therefore, accurately predicting the PM magnetic force during the assembly process is of paramount importance. The presented analytical solution is instrumental for designing PM assembly jigs across various machine sizes. A scaled-down experimental setup, incorporating a steel plate to neutralize magnetic forces, was employed. The experimental results and the analytical solutions are compared to validate the accuracy of the proposed calculations.