This paper deals with the optimization design process of an interior-type permanent magnet synchronous motor (IPMSM) for electric compressors of air conditioners applied to electric cars and hybrid vehicles. Based on a prototype IPMSM, we identified the current level for efficiency and cogging torque using finite-element analysis (FEA). The IPMSM’s main design variables are optimized to primarily satisfy the target of efficiency and cogging torque. A second optimization design is carried out using the response surface method (RSM) for the main design variables obtained from the Taguchi method analysis. As a result, the optimization design is carried out through a two-step optimization design process using the Taguchi method and RSM. The IPMSMs are analyzed using FEA, and their validity is confirmed by comparing the test results against each step-by-step model. We validate an effective optimization design process using a two-stage design process. We conclude that the proposed approach provides an effective design method for engineers.

This paper presents electromagnetic modeling and analysis of the detent force in a permanent magnet linear synchronous machine (PMLSM) according to auxiliary teeth configuration. Analytical solutions for magnetic fields generated by permanent magnets (PMs) are derived based on the Maxwell equation in terms of a two-dimensional Cartesian coordinate system. The magnetic vector potential of each subdomain (PM, air-gap, slot, and end region) is derived, and the field solution is obtained by applying the boundary and interface conditions between the subdomains. Based on the analytical solution, the magnetic force is derived by using the Maxwell stress tensor. All the analytical results were extensively validated using nonlinear finite element analysis and experimental results. Using the proposed method, we investigated the influence of the machine parameters on the detent force. Therefore, the proposed method can be very useful in the initial design and optimization process of PMLSM for detent force analysis.

This paper proposes an analytical technique for calculating the armature reaction field and inductance of permanent magnet linear synchronous machines based on a subdomain analytical model. The analytical solutions based on the subdomain model in terms of a two-dimensional Cartesian coordinate system are obtained using continuous and Neumann boundary conditions. The analytical results of the magnetic field are validated extensively with finite element method (FEM). Based on these solutions, the inductance is also determined analytically. In addition, we improve the accuracy of the analysis by using a simplified method of calculating the end inductance. Finally, the predictions are compared with a three-dimensional FEM and measured data to confirm the validity of the analysis methods presented in this paper.

This paper presents torque analysis and testing of an eddy current brake (ECB) with permanent magnets (PMs) using semi-three-dimensional (3D) analytical magnetic field calculations. The magnetic field solutions are obtained by considering the eddy current reaction using a 2D magnetic vector potential and 3D case by a simple and effective axial dependence modeling. The magnetic torque is also determined from these solutions. A finite element method (FEM) is employed to validate the analytical magnetic calculations. The braking torque measurement is experimentally verified to validate the analytical study. From the experimental study, we obtain analytical and 3D FEM results of braking torque with thermal behavior, and these are in good agreement with the experimental results.

In this paper, an exact analytical solution based on a Fourier analysis is proposed to compute the cogging torque in a surface-mounted permanent magnet synchronous machine. The analytical solutions are derived by solving the field-governing equations in each simple and regular subdomain, i.e., permanent magnet, air, slot opening, and slot, and then applying the boundary conditions to the interfaces between these subdomains. Based on these solutions, the cogging torque is also determined analytically. In order to verify the analytical results of the proposed method, an experimental system was implemented on a servomotor and torque sensor. All analytical results were extensively validated using nonlinear two-dimensional finite element analysis and experimental results. Using the proposed method, we investigated the influence on the cogging torque, according to the machine parameters. Therefore, the proposed method should be very useful in the initial design and cogging torque optimization of permanent magnet machines.

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.