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This article proposes a novel compact dual-permanent magnet (PM) dual-stator generator for hybrid ac/dc generation system. Two sets of windings are installed in the inner and outer stator separately. It has two electric ports, in which one is used to generate ac voltage and the other electric port that also generates ac voltage is rectified to obtain the dc voltage. The key of the generator is that two stators share one rotor with consequent PM structure, and the output power of the machine is much higher than that of the machine with only one stator. Besides, with two separated stator core and armature windings, the reliability of the proposed generator is improved. The advantage of the proposed dual-stator dual-PM generator is illustrated theoretically, and its slot/pole selection guideline is given. Comprehensive sensitivity analysis of the proposed generator is performed and multilevel design optimization method is adopted. The efficiency, torque ripple, and total harmonic distortion of the inner and outer armature windings of the generator after optimization are calculated to verify the effectiveness of the proposed machine design.

This paper proposes a novel direct-drive dual-PM motor for electric automatic guided vehicles (AGV). The proposed motor has split teeth on stator and dual PMs in stator and rotor sides, which contributes to reduced torque ripple, and enhanced torque. The airgap field of the proposed motor is analyzed theoretically, and the slot/pole selection guide line is concluded. The simulation results of the airgap flux density are shown and Fourier Transformation (FFT) analysis results agree well with the theoretically analyses results. Besides, the effects of design parameters of the proposed motor to the performances of the proposed motor are investigated. And it is found that reduced slot open could produce improved efficiency and decreased torque ripple. The efficiency of the proposed motor is relatively high within the operation range. A corresponding prototype is fabricated and the experiment validates the design.

In this article, the optimal configuration of the stator for the dual-permanent-magnet vernier machine (DPMVM) is investigated. A novel numerical model used to perform the optimization and compare the performances between different permanent magnet (PM) arrangements on the stator part is first presented in this article. According to the proposed numerical model, the effects of the location of PMs at different positions of the stator are studied in terms of output torque, torque ripple, efficiency, and power factor (PF). It is found that the PMs at stator slots contribute more to the output torque than PMs on stator teeth. Moreover, it is found that the stator PMs will add extra cogging torque to the machine compared with the rotor-PM machine. The PF of the dual-PM machine with the combination of the selected stator slots and rotor poles can be higher than 0.9, which is relatively higher compared with both the rotor-PM machine and stator-PM machine.

Biased flux machines (BFMs) have biased magnetic flux in the core and allows flexibility to adjust the field with a dc current. The conventional topology exploration methods for BFMs are based on the flux observation. It is time consuming and ineffective since the initial structure searching process is guideless. Meanwhile, BFMs usually work with arbitrary magnetic field harmonics instead of the fundamental one. The torque components of these machines and their essential operation principle have not been fully revealed. To solve these issues, in this paper, a topology exploration method for BFM based on magnetic field modulation mechanism is proposed, and the torque generating principle is analyzed. With this method, some new BFM structures have been developed and their torque components have been developed. It is shown that various space harmonics have contributed to constant torque rather than the fundamental one. To verify the feasibility of this design method, one double stator BFM is selected as a case study. Simulation and experimental results have verified that this design method is feasible and effective since the prototype has good sinusoidal back electromotive force waveforms and well performance. Besides, it is practical to realize flux weakening and strengthening the control with biased current.

In this paper, numerical method coupled with a novel model is proposed and applied to permanent magnet synchronous motor with reluctance-torque-assisted, aiming to obtain a motor with high efficiency, low torque ripple and maintain a good saliency ratio. Time-stepping finite-element-method coupled with multi-objective genetic algorithm is used to perform the further optimization. Through the proposed design method, the efficiency of the motor under rated condition will be improved and higher than 92% which can satisfy IE4 standard and the torque ripple is no greater than 5%, which is relatively low compared with the initial design.