Design Considerations of Sinusoidally Excited Permanent-Magnet Machines for Low-Torque-Ripple Applications

Islam, Mohammad; Mir, S.; Sebastian, Tomy; Underwood, S.

doi:10.1109/tia.2005.851026

Cited by 101 publications

(11 citation statements)

References 9 publications

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“…Small σ is a benefit for reducing end winding, thus less total copper and more compact design. As known that if the least common multiple N c between the number of rotor poles and stator slots is large, the peak value of the cogging torque in a PM machine will be reduced [32]. Moreover, for the symmetric distribution of the three‐phase windings, slots must be in multiple of three.…”

Section: Machine Designmentioning

confidence: 99%

Analysis, design and experimental verification of a field‐modulated permanent‐magnet machine for direct‐drive wind turbines

Chau

Cheng

2015

IET Electric Power Applications

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This paper presents the design and experimental verification of a field-modulated permanent-magnet (FMPM) machine using spoke-magnet outer rotor for direct-drive wind turbines. The fundamental operation and optimised design process of the proposed machine are elaborated and discussed in detail. The electromagnetic analytical calculation is used for the initial determination of the prototype design, mainly concerning the special constraints of wind power generation, and the twodimensional finite element analysis is also applied to optimise and investigate the detailed characteristics. A 5 kW prototype is constructed, and the measured performances have verified the analysis and design, justifying that the proposed machine can offer significant advantages of high-torque capability and low-voltage regulation. Experience gained from this study has led to develop a general design guideline for the open-slot FMPM machine using spoke-magnet outer rotor for direct-drive applications.

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Section: Machine Designmentioning

confidence: 99%

Analysis, design and experimental verification of a field‐modulated permanent‐magnet machine for direct‐drive wind turbines

Chau

Cheng

2015

IET Electric Power Applications

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“…The unequal permeance in the d and q axis produces the reluctance torque. The causes of torque pulsation coming from the supply are [9]: (d) Current ripple resulting, for example, from PWM. (e) Phase current commutation. Two different approaches are used to reduce torque ripple at present. The one is the optimal design of the motor ontology, such as air‐gap magnetic field, the structure of stator and rotor and winding structure, this method can eliminate cogging torque, and the back EMF waveform is approximate to ideal waveform [10–14]. The other approach uses advanced control strategy to minimise torque ripple, by adjusting phase voltage and current, the deviations of ideal properties are remedied [15–20].…”

Section: Introductionmentioning

confidence: 99%

Minimisation of torque ripple in slotless axial flux BLDC motors in terms of design considerations

Pahlavani

Ayat

Vahedi

2017

IET Electric Power Applications

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This study presents an analytical method to calculate instantaneous electromagnetic torque in slotless axial flux brushless DC (BLDC) motors. This method is based on Lorentz force theorem and using phase induced back electromagnetic force (EMF) and phase current. A new analytical method was introduced to compute induced back EMF. 3D finite element computations validate the proposed method. This method requires much less computation time than conventional 3D finite elements, and is therefore suitable for optimisation purposes. Due to practical limitation, phase current approximated by the trapezoidal function. Torque ripple dependency on design parameters was studied and optimum parameters were extracted for slotless axial flux BLDC motor.

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“…If it is excited with sinusoidal current with the third harmonic (sine + third current), the third harmonic current interacts with the third harmonic of electromotive force (back-EMF) and the torque can be enhanced. However, one of the drawbacks of the machine is that the torque ripple is significant due to cogging torque and back-EMF harmonics [11]. Torque ripples can be reduced by machine-or control-based techniques [12].…”

Section: Introductionmentioning

confidence: 99%

Magnet shape optimization of five‐phase surface‐mounted permanent magnet machine to improve torque performance based on equivalent permanent magnet method

Kang

Zhou

Wang

et al. 2015

IEEJ Transactions Elec Engng

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This paper studies the magnet shape optimization of a five-phase surface-mounted permanent magnet (PM) machine to improve its torque performance. First, a sinusoidal PM with third and fifth harmonics (sine + third + fifth PM) is presented to enhance the torque. An equivalent PM method is then proposed to avoid the complicated interface conditions between PM and the air gap, making the derivation of torques with magnet shapes using 2-D analytical models possible. Besides, the influence of PM edge thickness on torque improvement is considered. Moreover, under the condition that the copper losses of machines with different magnet shapes are kept unchanged, optimal harmonics of sinusoidal PM with third harmonic (sine + third PM) and sine + third + fifth PM are analytically derived. Finite element (FE) analysis is performed to validate the equivalent PM method and analytical results. Finally, machines with sine + third PM, sine + third + fifth PM and conventional (without shaping) PM are comparatively studied using nonlinear FE analysis and the experimental results of machine with sine + third + fifth PM are presented, verifying the effectiveness of the analytical optimization of magnet shape.

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Design Considerations of Sinusoidally Excited Permanent-Magnet Machines for Low-Torque-Ripple Applications

Cited by 101 publications

References 9 publications

Analysis, design and experimental verification of a field‐modulated permanent‐magnet machine for direct‐drive wind turbines

Analysis, design and experimental verification of a field‐modulated permanent‐magnet machine for direct‐drive wind turbines

Minimisation of torque ripple in slotless axial flux BLDC motors in terms of design considerations

Magnet shape optimization of five‐phase surface‐mounted permanent magnet machine to improve torque performance based on equivalent permanent magnet method

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