Yokeless and segmented armature (YASA) axial-flux permanent-magnet machine has high power density and efficiency, which is suitable for electric traction drive, especially for in-wheel or near-wheel direct-drive electric vehicles. This paper investigates and optimizes the cogging torque of the YASA machine with soft magnetic composite (SMC) core. First, the structure of YASA with SMC core is introduced. Then, the influence of magnet pole-arc ratio, magnet skewing, stator shoe width ratio, and stator shoe shifting on cogging torque is analyzed, based on which the cogging torque is optimized by establishing the response surface model and using the genetic algorithm. Finally, the optimization results are verified by the 3-D finite-element method. The results confirm that based on a certain magnet pole-arc ratio, there exists an optimum combination of magnet skew angle, stator shoe width ratio, and stator shoe shift angle for the cogging torque minimization, while the main performances of the machine remain nearly invariable.

Traditional surface permanent magnet synchronous motor (SPMSM) used as a servo motor limits the miniaturization and performance improvement of industrial robot, due to — its large overall volume and heavy weight of the rotor. In this paper, a novel transverse flux permanent magnet motor with a hybrid stator core and disk-type rotor (HSDR-TFPM) is proposed to adapt to the industrial robot well. Moreover, a better space design by which the usual components used in industrial robot is considered. Considering the computing time and accuracy, an analysis method based on Schwarz-Christoffel (SC) mapping is employed to analyze the magnetic field of HSDR-TFPM and conduct research on motor parameters. In order to prevent the axial movement of rotor, the detailed mechanical design is introduced and the strength of motor is analyzed furtherly. In the end, the analysis results and performance of the proposed HSDR-TFPM are validated and compared with a conventional servo SPMSM.

A novel transverse-flux permanent magnet linear motor (TFPMLM) named as double-sided double-excited one is proposed in this paper. First, the operational principle and structural advantages of the TFPMLM are presented. Then, the 3-D magnetic circuit structure of the TFPMLM is simplified equivalently into a 2-D one in order that Schwarz-Christoffel (SC) mapping method can be adopted to analyze the motor's magnetic field and characteristics. Then, the air-gap flux density distribution, back voltage and force waveforms when at no-load and at load are calculated by the SC mapping method and 3-D finite-element method, respectively, for a prototype linear motor, The results from the two methods coincide much better with each other. At last, influences of magnet shape on the cogging force are studied by the SC method.

Transverse flux permanent magnet motor (TFPM) benefits from the high power density and design freedom but traditional TFPM exhibits some disadvantages-high flux leakage, cogging torque, and low-power factor-which restrict its development. In order to overcome these disadvantages, claw pole TFPM (CTFPM) is developed, but it also be plagued by the demerits of soft magnetic composite (SMC) material. In this article, a novel CTFPM based on hybrid stator core (Hybrid-CTFPM) is proposed to improve the performance of CTFPM. The parameters of claw pole are investigated in this article and are optimized using a new optimization strategy eventually. This article provides a valuable reference for the design and optimization of CTFPM.

Using the finite-element model (FEM) to achieve the optimal design of electromagnetic devices is a complex and time-consuming process. Space-mapping techniques reduce computation cost by aligning two models with different granularities, namely, a coarse model and a fine model. In this paper, Kriging output space mapping (OSM), an original space-mapping technique based on adaptive nonlinear corrective projection, is proposed and compared with a conventional OSM technique. The device for optimal sizing is a five-phase linear induction motor, which is represented through two modeling levels: 1) coarse (Kriging model) and 2) fine (2-D FEM). An advantage of this new technique is its ability to provide a sufficiently accurate model for each objective and constraint function and make the coarse model converge effectively toward the fine model.

In order to solve a series of problems such as electromagnetic loss, mechanical strength, rotor dynamics, and vacuum cooling induced by the high-power machine in flywheel energy storage system (FESS), a multiphysics coupling field of electricity, magnetism, stress, thermal and fluid is adopted to conduct a comprehensive analysis of a high-capacity FESS. Firstly, a structure of high-power cup winding permanent magnet synchronous machine (PMSM) for wind power frequency regulation is proposed in this paper of which the electromagnetic characteristics are analyzed by the finite element method (FEM). Secondly, the temperature of the flywheel under vacuum environment is analyzed by establishing a fluid-solid coupling thermal model. After that, the mechanical strength of the machine is researched based on the theory of elasticity and thermal coupling, and the rotor dynamics is studied by modal analysis. Finally, an overall prototype of the FESS is fabricated and the performance of electromagnetic, stress and temperature are validated. The experimental results verify the relevant theories and simulation analysis, which can finally realize the reliable operation of the high-capacity FESS.