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This paper presents a new rotor shape design with optimum reverse 3rd harmonic for wound field synchronous machines to effectively enhance the saliency ratio and reduce the torque ripple in a micro electric vehicle traction system. Due to the enhanced saliency ratio, the reluctance torque is expected to be improved. The air gap flux density distribution is reshaped by the new rotor shape method, which benefits the low torque ripple. By contrast, the reverse 3rd harmonic injection is much more suitable than the general 3rd harmonic injection for increasing the effective air gap length along the q-axis for a high saliency ratio. Subsequently, three amplitudes of the reverse 3rd harmonic are studied and it is found that the optimum reverse 3rd harmonic is 1/6 of the fundamental one. To verify the effectivity of the proposed design, the original model and the ICS model are compared. Finally, all the motor characteristics, such as back electromotive force, cogging torque, and electromagnetic torque, are predicted using a 2-D finite-element method with the aid of JMAG-Designer. [ABSTRACT FROM AUTHOR]

This paper proposes an optimal design for a salient pole wound field synchronous machine (WFSM) with a single flux barrier to improve torque performance and obtain a wide operating range, simultaneously. The proposed WFSM motor can effectively decrease q -axis inductance to improve the saliency ratio ( X_{d}/X_{q}) and increase the reluctance torque. To maximize the saliency ratio and improve the torque characteristics, the single flux barrier is optimized, considering the magnetic saturation that uses Kriging method based on Latin hypercube sampling and a genetic algorithm. The 2-D finite element analysis results by the aid of JMAG-Designer shows that the saliency ratio X_{d}/X_{q}$ , the reluctance torque, and the total torque of the optimal model are increased by 9.27%, 20.45%, and 6.17%, respectively, compared with those of the basic model. Finally, the performance of the optimal motor is verified through an experimental test, which indicates good agreement with the simulation results. [ABSTRACT FROM AUTHOR]

In this paper, a misalignment-tolerant wireless charging system based on multidimensional cross-coupling for autonomous underwater vehicles (AUVs) is proposed. The four transmitting coils of the proposed system magnetic coupler are divided evenly into two pairs as bipolar transmitting units. Subsequently, the uniform multi-dimensional horizontal magnetic flux can be obtained by two current vectors with a 90° phase difference exciting in the bipolar transmitting units. For the receiver, a couple of orthogonal coils are designed to form cross-coupling with the transmitter to pick up the maximum magnetic flux. Then, the proposed magnetic coupler combined with the proposed transmitter and receiver is designed through finite element analysis. Finally, a 900 W prototype is built and tested. Experimental results show that the system has stable output characteristics in the ranges of a − 20° to 20° rolling misalignment and a − 30 to 30 mm axial misalignment. [ABSTRACT FROM AUTHOR]