This paper proposes a new equivalent magnetic network (EMN) model for vehicular dual-permanent-magnet vernier (DPMV) machines by applying a generalized modeling method. Firstly, the magnetic circuit method and the meshing method are combined together to model the DPMV machine effectively. The magnetic circuit is used to generate conventional equivalent permeances to shorten time consumption, while the mesh method is utilized in disordered magnetic fields to obtain high precision. Secondly, a meshing solution for oblique region is proposed to enhance modeling flexibility. Moreover, the flux distributions in meshes are represented without magnetic field pre-delineation, which enables its utilization as a self-adaptive reluctance network model in design optimization. Finally, the proposed EMN model is used to predict the performance of a DPMV machine, considering leakage magnetic flux, local iron saturation and magnetic field modulation effect simultaneously. Meanwhile, the effectiveness of the proposed EMN model is verified by comparison with finite-element analysis and experimental tests.

The coreless axial flux permanent magnet synchronous motor with printed circuit board stator (PCB motor for short) has attracted research interests for many advantages, such as flexible and precise winding design, low toque ripple, noiseless operation and simple manufacturing process. The motor performance, however, highly depends on its wiring design, which should be carefully optimized. In this article, an arc-shaped distributed winding is adopted due to its higher efficiency. The PCB motor has a 3D magnetic field distribution, which makes its optimal design very difficult since the 3D finite element analysis is usually required. In this article, an analytical model of PCB motor including 3D magnetic field, arc-shaped winding flux linkage and eddy current loss is firstly deduced. On this basis, a multi-objective optimal design is then carried out to design a PCB motor for a vacuum cleaner. Compared with the concentrated winding, the arc winding can achieve a 3% efficiency improvement. Finally, a 130 W prototype and testbench were built and the presented analytical model is verified by experiments. The results show that there is little difference between calculation and experiment. The presented method effectively simplifies the design process of this kind of motor and shortens the design time.

As one of the key issues of interior permanent magnet (IPM) motors in the matching of electric vehicles (EVs), the design and optimization of the rotor are greatly fundamental. This article performs the design and optimization of IPM motors for EVs considering rotor topology and manufacturing uncertainty. First, the contribution of different rotor topologies to a variety of motor performances is investigated, and the results show that the IPM motor with V-type rotor topology is more satisfying with comprehensive performance competitiveness. Then, robust optimization and design of the V-type motor are carried out to further improve the motor performance robustness. On one hand, the influences of manufacturing uncertainties on motor performance fluctuation are suppressed by using an improved robust optimization algorithm. On the other hand, rotor notch is adopted as an alternative method of rotor skew, to avoid the manufacturing uncertainties introduced by the rotor skew process as well as reduce torque ripple. Finally, based on the simulation results and theoretical explanation, a prototype is assembled and the experimental results verify the validity of the results presented in this article.

In this paper, an asymmetric rotor interior permanent magnet (ARIPM) motor with high demagnetization prevention capability and robust torque performance is proposed. The key contribution of this paper lies in two aspects. On the one hand, a novel asymmetric rotor with a shifted magnet axis is proposed to improve the demagnetization prevention capability and torque density. In order to obtain a proper asymmetric rotor topology of the ARIPM motor, the multi-physical performances, especially the PM demagnetization characteristics of five types of PM arrangements, are analyzed. Furthermore, an asymmetric rotor with V- and VV-type PM arrangement is preliminarily designed, considering the multi-physical performance balance and the potentially high anti-demagnetization ability. On the other hand, it is found that the asymmetric rotor structure can not only improve the nominal value of motor performance but also can enhance the resistance to the influence of manufacturing uncertainties. Therefore, multi-objective optimization of the ARIPM motor with rotor notch design is carried out to obtain an optimal motor structure with both high nominal value and robustness of motor performances. By comparing the simulation results with those of a benchmark motor, the superiority and validity of the proposed ARIPM motor are confirmed. Experimental tests will be carried out in the future to further verify the effectiveness of the proposed motor.

This article presents an effort to develop an effective method for the robust design optimization of a hairpin winding permanent magnet motor. The comprehensive influence of variable uncertainties due to PM property inconsistency and manufacturing uncertainties is considered. During the implementation of robust design optimization of the hairpin winding permanent magnet motor by using an evolution-based multi-objective optimization algorithm, one major obstacle is the huge computation cost, especially for the robust analysis process. Therefore, a two-level solution strategy, an adaptive least square support vector regression model, and a novel dominant judging condition are skillfully employed to realize the tradeoff between the computation cost and accuracy of the robust design optimization algorithm. To verify the effectiveness of the proposed method, the fluctuation and distribution of electromagnetic performance of the robust motor design are analyzed and compared with those of a deterministic motor design. Finally, a prototype of the hairpin winding permanent magnet motor is manufactured and tested to further confirm the validity of the proposed method.