The saturation magnetic density is lower due to the silicon content of the conventional motor core made of Non Grain-Oriented (NGO) silicon steel. It is increasingly difficult to meet the demand for high power density and high torque density of modern motors. Based on the above reasons, this paper proposed the idea of replacing the NGO silicon steel core by the Grain-Oriented (GO) silicon steel core part through a combined design. This paper mainly presents a novel thin an-isotropic GO silicon steel core used in high-speed (up to 14500rpm) traction motors. Magnetic saturation, power loss, thermal conductivity, and mechanical property analysis of the motor have been completed. Numerical modeling and experimental results have been given. The new prototype is being fabricated and it can be produced in mass production in the next few years.

Nowadays, energy shortages and environmental pollution have received a lot of attention, which makes the electrification of transportation systems an inevitable trend. As the core part of an electrical driving system, the electrical machine faces the extreme challenge of keeping high power density and high efficiency output under complex workin g conditions. The development and research of new soft magnetic materials has an important impact to solve the current bottleneck problems of electrical machines. In this paper, the variation trend of magnetic properties of ultra-thin grain-oriented silicon steel electrical steel (GOES) under thermal-mechanical-electric-magnetic fields is studied, and the possibility of its application in motors is explored. The magnetic properties of grain-oriented silicon steel samples under different conditions were measured by the Epstein frame method and self-built multi-physical field device. It is verified that the magnetic properties of grain-oriented silicon steel selected within 30° magnetization deviation angle are better than non-grain-oriented silicon steel. The magnetic properties of the same ultra-thin grain-oriented silicon steel as ordinary non-oriented silicon steel deteriorate with the increase in frequency. Different from conventional non-grain-oriented silicon steel, its magnetic properties will deteriorate with the increase in temperature. Under the stress of 30 Mpa, the magnetic properties of the grain-oriented silicon steel are the best; under the coupling of multiple physical fields, the change trend of magnetic properties of grain-oriented silicon steel is similar to that of single physical field, but the specific quantitative values are different. Furthermore, the application of grain-oriented silicon steel in interior permanent magnet synchronous motor (IPM) for electric vehicles is explored. Through a precise oriented silicon steel motor model, it is proved that the magnetic flux density of stator teeth increases by 2.2%, the electromagnetic torque of motor increases by 2.18%, and the peak efficiency increases by 1% after using grain-oriented silicon steel. In this paper, through the investigation of the characteristics of grain-oriented silicon steel, it is preliminarily verified that grain-oriented silicon steel has a great application prospect in the drive motor (IPM) of electric vehicles, and it is an effective means to break the bottleneck of current motor design.

This paper presents the rotor optimization in an interior permanent magnet synchronous machine (IPMSM) with high-strength non grain-oriented (NGO) silicon steel material. Different from simple replacement with high-strength NGO, this paper presents a customized design to make the best use of rotor iron core material. Specific optimization of the rotor topology is presented, followed with simulation verification by finite element method (FEM). Based on the simulation results, the benefits and limitations of the optimization design with the replacement of high-strength NGO are listed. In order to further overcome the limitations of the presented optimization design, magnetic characteristics of the high-strength NGO laminations subjected with various tensile stress are measured in experiment. Finally, experimental results are analyzed, and the conclusions to employ high-strength NGO for IPMSM are summarized.

In this paper, an iron loss model considering multiphysics fields is proposed and applied in a high-speed axial flux permanent magnet motor (HSAFPM). The investigated HSAFPMs are fabricated using winding cores of conventional silicon steel (CSS) with a thickness of 0.27 mm and ultra-thin silicon steel (UTSS) with a thickness of 0.05 mm, respectively. The wound technique makes axial flux motors easier to manufacture, but induces bending stresses. Therefore, the core loss of the motor is affected by the interaction of high frequency electromagnetic field, temperature and bending stress. The article analyses the difference of bending stress induced by silicon steel sheets with different thicknesses, and according to the operating conditions of the motor, the magnetic properties of silicon steel under the bending stress-temperature-electromagnetic multiphysics field coupling conditions are analyzed, and an iron loss model considering multiphysics fields is proposed. The validity of the proposed model is verified by experiments on silicon steel sheets with multiphysics fields, and the accuracy is improved compared with existing models. Finally, two motors with different core material thicknesses are fabricated and the proposed iron loss model is verified in the motor using the finite element method for more accurate calculation of motor iron loss.

As a device that realizes the "static-to-motion" transformation which influences the national economy and people’s livelihood, the Electric Machine (EM) has put forward higher requirements for the torque/power density with the development of industry. It is difficult to meet the new requirements by using traditional silicon steel. Therefore, the application of "new" materials has become a breakthrough point. This paper studied the properties and the application of Fe-Co-V alloys (1J22) which has a high saturation magnetic polarization, then analyzed its performance in high torque density EMs. Since the stator field is a rotating magnetic field which changes with time, the variable-angle magnetic performance test was carried out on 1J22 to discuss the influence of the magnetic performance under different shear angles on the stator magnetic flux. The EM’s design and prototype production were carried out for the unique properties of the 1J22 material itself. Compared with the EM model using traditional non grain-oriented(NGO) silicon steel 35ADG1900, the use of 1J22 material can solve the temperature rise problem under special working conditions. At the same time, the feasibility of 1J22 in high torque density traction motor has been verified.

Because the magnetic properties of an amorphous alloy (AA) obviously change with the change of temperature, a finite element simulation method for a motor, considering the effect of temperature, is proposed in this paper. In the early design stage of the high-speed permanent magnet synchronous motor (PMSM), the simulation of motor performance is mainly based on the magnetic performance test data at room temperature provided by the material’s manufacturer. However, the influence of the temperature rise during the actual operation of the motor will lead to large errors between the simulation results and the measured results. Therefore, it is of great practical significance to measure the magnetic properties of the AA at different temperatures and use them for simulation purposes. In this paper, the magnetization characteristics and iron loss characteristics of the AA and silicon steel (ST100) used for comparison are measured at different temperatures, and the iron loss separation of the two materials at different temperatures is completed, and the hysteresis loss coefficient and eddy current loss coefficient at different temperatures are obtained. On this basis, the performance simulation of a motor model is carried out. The more accurate simulation method proposed in this paper can provide a reference for the design of AA motors in industry.