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In this article, a parallel-series magnetic circuit multi-permanent magnet (M-PM) motor is designed and optimized considering magnet characteristic variation effects, where two kinds of permanent magnets (PMs) are utilized as co-magnetic. Based on the equivalent magnetic circuit method, the detailed design method for the M-PM motor is illustrated. Considering the various operation conditions in potential electric vehicle applications, the B–H curves of two PMs of different typical operation conditions are obtained. Then, a multiobjective optimization method is newly proposed which not only focuses on the magnet characteristics variation effect but also considers output torque, torque ripple as well as antidemagnetization capability under three typical operation conditions. The performances of the initial motor and optimal motor are compared under typical operation conditions. Finally, a prototype machine is built and tested. Both theoretical analysis and experimental results verify the validity of the motor and the proposed design optimization method. [ABSTRACT FROM AUTHOR]

In this article, a flux-controllable permanent magnet (FC-PM) motor has been designed and optimized to achieve the optimal torque component distribution under different flux leakage conditions. The FC-PM motor can realize flexible adjustment and control of air-gap magnetic field by a reasonable flux bridge design, which further broadens the speed range of the motor effectively. The focus of the research is to analyze and optimize the torque characteristics in combination with typical operation conditions. First, a motor topology is proposed and then the mechanism of flux leakage and the distribution of torque characteristics are studied. Then, according to different flux leakage operation conditions, an optimization method considering the torque component distribution is newly proposed. Based on the proposed optimization method, the optimal motor can be obtained. Finally, the performance of the optimal motor is analyzed and compared with the initial motor. The comparison results indicate that, based on the proposed optimization method, the torque output capability is improved effectively, while the desired leakage flux adjustment range is maintained. [ABSTRACT FROM AUTHOR]

In this article, based on flux modulation theory, an airgap-harmonic-based multilevel optimization design approach is proposed for a double-stator flux-modulated permanent-magnet (DS-FMPM) motor. The proposed DS-FMPM motor is purposefully designed, so as to realize the design requirements of driving cycle. In the proposed optimization approach, based on three fundamental elements of general flux modulation theory, motor optimization design is carried out from three levels. Furthermore, a response surface method, sensitivity analysis, and a genetic algorithm are purposely employed in different levels to obtain optimal motor design. In addition, electromagnetic performances of a DS-FMPM motor are demonstrated in detail. Finally, a prototype motor is manufactured and tested. Both simulation and experimental results verify the feasibility of the DS-FMPM motor and the effectiveness of the proposed airgap-harmonic-based multilevel optimization design approach. [ABSTRACT FROM AUTHOR]

In this article, a variable-saliency-ratio permanent magnet motor is designed and optimized considering driving cycles. To satisfy the demands of multi-operation conditions of EVs, a variable resistance is adopted and a new variable-saliency-ratio design concept is proposed to enhance output torque, widen speed range and lower irreversible demagnetization risk effectively. A multiobjective optimization considering driving cycles is proposed, where the design objective of saliency ratio is firstly selected and optimized with multiobjective genetic algorithm method. Then, the operation performances of the motor in different operation conditions are investigated in detail. Finally, a prototype motor is built and tested. Both the simulation and experimental results verify the validity of the proposed method. [ABSTRACT FROM AUTHOR]

In this article, a new type of flux-intensifying permanent magnet (FI-PM) motor is designed, analyzed, and optimized. It focuses on the low-speed operation condition of electric vehicles (EVs). The key characteristic of this motor is the feature of the reverse saliency, so that it not only utilizes the positive reluctance under the positive $d$ -axis current but also improves the PM operation point under maximum torque per ampere (MTPA) control strategy. The relationships among the key parameters, reverse saliency, and torque performance are analyzed and investigated. The response surface method is used to optimize the motor performances. Then, for a better presentation of the investigated motor, the motor performances are evaluated and compared with the traditional interior permanent magnet motor (IPM) in torque characteristic and irreversible demagnetization ability. Finally, for the experimental validation, the prototyped motor is manufactured and tested. [ABSTRACT FROM AUTHOR]

The price fluctuation and the unstable supply chain of rare-earth permanent magnet (PM) have posed potential risks for further application of rare-earth PM motors. To alleviate the consumption of rare-earth PM material, a less-rare-earth PM brushless motor with two types of PM materials is proposed in this paper. The key of this motor is that the rare-earth PM is purposely combined with a non-rare-earth ferrite PM, forming the hybrid PM excitation. To design the proposed motor efficiently, a multi-objective stratified optimization strategy is proposed, where the selected five optimization objectives of output torque, PM cost, cogging torque, torque ripple, and efficiency are divided into two levels. Then, different optimization methods are skillfully combined to meet the specific design requirements. The corresponding electromagnetic performances are analyzed and compared with the baseline rare-earth PM brushless motor. Finally, several experiments of the two motors are carried out for evaluation. Both theoretical analysis and experimental results verify the feasibility and validity of the proposed motor and the optimization method. [ABSTRACT FROM AUTHOR]

In this paper, two permanent magnet flux-intensifying motors are designed and optimized to realize the characteristic ofLd>Lqand the flux-intensifying effect. Compared with the conventional interior permanent magnet motor with the characteristic ofLd< Lq, the advantages of a low irreversible demagnetization risk and a wide speed range can be obtained in the motors. To meet multiple design requirements effectively, a comprehensive sensitivity analysis method is first implemented to evaluate the influence of each design variable on the selected optimized objectives of output torque, reverse saliency ratio, and torque ripple. Second, a sequential nonlinear programming algorithm is used for realizing the multiobjective optimizations of strong-sensitive design variables. Then, the performances of the two optimal motors are analyzed and compared with the initial permanent magnet motor in detail. Finally, two prototype motors are manufactured and tested. Both the simulation and experimental results verify the validity of the new flux-intensifying motors and the optimization method. [ABSTRACT FROM AUTHOR]

In this paper, two new flux-intensifying interior permanent magnet (FI-IPM) motors owing the characteristic ofLd>Lqare proposed for extended operating speed range. The feasible approaches of realizingLd>Lqare first discussed to emphasize rotor flux barrier design. According to the feasible approaches, interior flux barriers and surface flux barriers combined with different PM placements are adopted in these two motors. To verify the proposed approaches and the validity of motors, a comprehensive investigation and comparison between the two motors are carried out, including both electromagnetic performances and mechanical performances. By comparison, a prototype motor possessing lower torque ripple, lower magnetic saturation, wider speed range, and more robust mechanical property is manufactured and tested. The experiment results verify the characteristics of the proposed motors and the validity of the proposed approaches in FI-IPM motor design. [ABSTRACT FROM AUTHOR]

This paper proposes a brushless double mechanical port flux-switching permanent-magnet motor for potential application in hybrid electric vehicles. To realize the design objectives of high-torque capability, low-torque ripple, and low-magnetic coupling between the inner and outer motors, a new multilevel design optimization method is proposed to conduct a multiobjectives optimization. First, by adopting the comprehensive sensitivity approach, the whole optimization design process is divided into three levels: nonsensitive level, mild-sensitive level, and strong-sensitive level. Then, to improve the whole design efficiency, the response surface method and multiobjective genetic algorithm are applied in the mild-sensitive level and strong-sensitive level, respectively. Based on the proposed design method, a compromise design among the three design objectives is considered and realized. Finally, a prototype motor is built to verify the validity of the proposed design method and motor operation. [ABSTRACT FROM PUBLISHER]

Permanent magnet brushless (PMBL) motors have been widely applied in electric vehicles, since they inherently offer high efficiency, high power density, and free maintenance. However, because of the existing problem of uncontrollable flux, their constant-power speed range is relatively narrow. In order to gain a wide speed range, by employing the new concept of the flux-intensifying effect, a new flux-intensifying PMBL (FI-PMBL) motor is proposed in this paper. The proposed motor is innovatively designed, where the topology of two-layer segmented PMs and non-uniform air gap are adopted to make the corresponding d -axis inductance L_{d} become greater than the q$ -axis inductance L_{q} , which is far different from the conventional interior PM motor. By using the finite-element methods, the electromagnetic performances of the proposed motor are evaluated in detail. Simulation results show that the proposed motor possesses preferable flux-weakening capability and wide speed range. In addition, the experimental results of the FI-PMBL prototype are given to verify the performances of the motor. [ABSTRACT FROM PUBLISHER]

In this paper, an interior permanent magnet (IPM) synchronous machine with multiflux barriers is proposed to meet the wide speed regulation application requirements of electric vehicles. Based on the flux barrier characteristic, an electromagnetic–mechanical coupling optimization strategy is employed for the machine design. In order to facilitate the optimization design, the rotor barriers are divided into two optimization zones, the maximum stress zone and the maximum deformation zone. The electromagnetic–mechanical coupling optimization strategy is divided into two stages accordingly. In the first stage, the machine is regarded as a synchronous reluctance machine by ignoring permanent magnets, where the dimensions of the arc-shaped barriers are optimized to achieve a large reluctance torque and small stress. In the second stage, the dimensions of the arc-shaped PMs and the elliptical barrier are optimized with three objectives of minimum torque ripple, minimum flux linkage, and minimum deformation. After machine optimization, the comparison investigations are carried out on the basis of finite-element analysis by considering both the electromagnetic performances and mechanical performances. [ABSTRACT FROM AUTHOR]