New core structure and manufacturing method for high efficiency of permanent magnet motors

Akita, Hiroyuki; Nakahara, Yuji; Miyake, Nobuaki; Oikawa, Tsukasa

doi:10.1109/ias.2003.1257527

Cited by 62 publications

(27 citation statements)

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“…Concentrated windings offer some significant advantages over distributed windings. These include: 1) significant reduction in the copper volume and copper losses in the end region; 2) significant reduction in the machine total length [3], [4]; 3) reduction in machine manufacturing cost; and 4) compatibility with segmented stator structures that makes it possible to achieve significantly higher slot fill factor values [8], [9].…”

Section: Concentrated Windings and Flux Weakeningmentioning

confidence: 99%

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Optimal Flux Weakening in Surface PM Machines Using Fractional-Slot Concentrated Windings

El-Refaie

Jahns

2005

IEEE Trans. on Ind. Applicat.

356

104

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Abstract-A design approach is presented for achieving optimal flux-weakening operation in surface permanent-magnet (SPM) synchronous machines by properly designing the machine's stator windings using concentrated, fractional-slot stator windings. This technique makes it possible to significantly increase the machine inductance in order to achieve the critical condition for providing wide speed ranges of constant-power operation. The conditions for optimal flux weakening can be achieved while simultaneously delivering sinusoidal line-to-line back-electromotive-force waveforms and low cogging torque. A closed-form analytical model is described that can be used to design SPM machines to achieve optimal flux-weakening conditions. This technique is applied to design a 6-kW SPM machine that achieves constant-power operation over a wide speed range. Performance characteristics of this machine are compared using both closed-form and finite-element analysis.

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Section: Concentrated Windings and Flux Weakeningmentioning

confidence: 99%

“…It is worth noting here that concentrated windings are compatible with segmented stators that break the stator into individual stator tooth poles [7]- [9]. Segmented stator poles make it possible to wind the solenoidal windings much more tightly than it is possible to do with conventional stator laminations.…”

Section: G Current Densitymentioning

confidence: 99%

Optimal Flux Weakening in Surface PM Machines Using Fractional-Slot Concentrated Windings

El-Refaie

Jahns

2005

IEEE Trans. on Ind. Applicat.

356

104

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“…Unlike DW, which overlap one or more stator teeth, CW are wound around individual stator teeth. The coil around individual stator teeth can take advantage of more advanced winding methods, such as the joint lapped core methods [35,37] and use of modular stator tooth pieces [36]. These methods claimed to achieve up to 75% and 78% slot-fill factor respectively.…”

Section: Stator Winding Copper Lossesmentioning

confidence: 99%

Analysis and Experimental Verification of Losses in a Concentrated Wound Interior Permanent Magnet Machine

Dutta¹,

Chong²,

Rahman³

2013

PIER B

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Abstract-It is well known that additional space harmonics in the air-gap magnetomotive force (MMF) distribution of the concentrated non-overlapping windings (CW) cause additional losses in the machine. This is especially so for machines used for traction applications where the machine requires to operate over its rated speed and frequency. In this paper, the authors investigates losses present in an interior permanent magnet (IPM) machine with CW designed to achieve a very wide field weakening range. Losses were quantified analytically and also using finite element methods.Loss estimations were experimentally verified in a constructed prototype machine. Based on the analysis, key losses were identified. The optimization process to minimize these losses and of improving efficiency were discussed in details. The segregation of the losses in the studied machine indicates that the losses in the magnet are much smaller compared to the rotor and stator core losses caused by the slot harmonics. Therefore, core loss minimization techniques for this type of machine will involve reduction of slot harmonics. Also, copper loss is found to be the most dominating component of the total loss. Hence, copper loss minimization should be part of the design optimization process.

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“…To be consistent, this has been carried out for both the predicted and measured d-axis inductances. (5) where and are the dc components of the self-and mutual-inductances, respectively. and are the 2 nd order harmonics in the self-and mutual-inductances, respectively.…”

Section: A Modular Spm Machines With Healthy Rotormentioning

confidence: 99%

“…In order to improve the fault tolerance capability and also to simplify the manufacturing process, particularly for large PM machines, the modular topologies (segmented stator and/or rotor) have been introduced in the last decades [1] [2] [3] [4]. Due to the specific segmented stators, these modular machines can overcome the main drawbacks of conventional modular machines such as reduced average torque and increased torque ripple [5] [6]. This is mainly due to the fact that the flux gaps in alternate stator teeth as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Demagnetization Withstand Capability Enhancement of Surface Mounted PM Machines Using Stator Modularity

Ren

Zhu

et al. 2018

IEEE Trans. on Ind. Applicat.

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-The flux gaps in alternate stator teeth of the modular PM machines can have a significant impact on the total magnet flux density, and hence, the potential magnet reversible/irreversible demagnetization under flux weakening operations or short-circuit conditions. Such a problem has not been studied in literature and will be investigated in this paper. The influence of flux gaps on the d-axis inductance and the potential peak short-circuit current is analysed for different slot/pole number combinations. It is found that the flux gaps will affect both the d-axis inductance and open-circuit flux linkage, and hence reduce short-circuit current of machines with pole number (2p) smaller than slot number (N s ) while they will increase the short-circuit current of machines with 2p > N s . However, the opposite phenomena can be observed for demagnetization withstand capability. For machines having 2p < N s , the flux gaps tend to lower withstand capability, whilst for machines having 2p > N s , this capability can be improved. Other parameters, such as magnet thickness, temperature, etc., have also been accounted for in the demagnetization analysis. Tests have been carried out to validate the predictions of inductances and short-circuit current as well as performance such as phase back-EMF, cogging torque and static torque for machines with one defective magnet, which represents the case of partially demagnetized magnets. Index Terms -demagnetization withstand capability, flux gap, modular machine, permanent magnet, short-circuit current.

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New core structure and manufacturing method for high efficiency of permanent magnet motors

Cited by 62 publications

References 0 publications

Optimal Flux Weakening in Surface PM Machines Using Fractional-Slot Concentrated Windings

Optimal Flux Weakening in Surface PM Machines Using Fractional-Slot Concentrated Windings

Analysis and Experimental Verification of Losses in a Concentrated Wound Interior Permanent Magnet Machine

Demagnetization Withstand Capability Enhancement of Surface Mounted PM Machines Using Stator Modularity

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