Review of Design Solutions for Internal Permanent-Magnet Machines Cogging Torque Reduction

Bianchini, Claudio; Immovilli, Fabio; Lorenzani, Emilio; Bellini, A.; Davoli, Matteo

doi:10.1109/tmag.2012.2199509

Cited by 75 publications

(41 citation statements)

References 21 publications

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“…Some work was done on calculating and reducing the cogging torque of transverse flux machines, including the traditional transverse flux machine [4] and flux switching transverse flux machine [5]. Both the analytical method [6,7] and numerical method [8,9] were used to calculate the cogging torque in PMSMs, and various kinds of technologies were developed to reduce the cogging torque in the radial-flux and axial-flux PMSMs [10,11]. These methods can be classified into two ways: one is based on the control method [12], and the other is based on the optimized structure of the PMSM [13].…”

Section: Introductionmentioning

confidence: 99%

Techniques for Reduction of the Cogging Torque in Claw Pole Machines with SMC Cores

Liu

Wang

et al. 2017

Energies

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Abstract:As one of the main parasitic parameters in permanent magnet (PM) synchronous machines (PMSMs), cogging torque is the main component of the torque ripple, which has always been the handicap in the high-performance, low-speed drive systems. Over the last two decades, various methods have been proposed to decrease the cogging torque in both radial-flux and axial-flux PMSMs. Among these methods, stator slot skewing, stator tooth notching, PM skewing, PM shifting, and pole pairing are extensively investigated. However, little work has been done on reducing the cogging torque of the claw pole machine (CPM), whose cogging torque cannot be ignored. In this paper, the general methods that have been used to reduce the cogging torque in radial-flux and axial-flux PMSMs are developed and verified in a CPM with a soft magnetic composite (SMC) core. The 3-D finite element method (FEM) is used to calculate the cogging torque and PM flux linkage per turn. By comparing different cogging torque reduction technologies, it can be found that the magnet step skewing and unequal claw pole width are very suitable for CPM.

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Section: Introductionmentioning

confidence: 99%

Techniques for Reduction of the Cogging Torque in Claw Pole Machines with SMC Cores

Liu

Wang

et al. 2017

Energies

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“…The cogging torque is caused by interactions between the permanent magnets mounted on the rotor and the anisotropy due to stator slots [4]. Because of this anisotropy the magnetic field energy changes during the rotation and a torque is produced which can be expressed as:…”

Section: Cogging Torque Analysismentioning

confidence: 99%

“…However, their operations are negatively impacted by cogging torque [3,4]. Cogging torque reduces the torque quality by producing undesired vibration and mechanical noise, which seriously impact the machine performance especially in low speed and direct drive applications [5].…”

Section: Introductionmentioning

confidence: 99%

“…Researchers have investigated different methods for reducing the cogging torque. Slot skewing [4] and [8], magnet skewing [9], auxiliary slots or teeth [10] and [11], pole-arc optimization [12] to [15], slot or tooth paring [16], magnet segmentation [17] and [18], magnet shifting and shaping [9,13] to [15,19] and [21] are examples of the solutions have been proposed in the literature for reducing cogging torque. Although these techniques are successful in reducing the undesired cogging torque, but they can also reduce the desired mutual torques.…”

Section: Introductionmentioning

confidence: 99%

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Cogging Torque Reduction in Line Start Permanent Magnet Synchronous Motor

Behbahanifard¹,

Sadoughi²

2016

Journal of Electrical Engineering and Technology

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-Cogging torque has a negative impact on the operation of permanent magnet machines by increasing torque ripple, speed ripple, acoustic noise and vibration. In this paper Magnet Shifting Method has been used as a tool to reduce the cogging torque in inset Line Start Permanent Magnet Synchronous Motor (LSPMSM). It has been shown that Magnet Shifting Method can effectively eliminate several lower-order harmonics of cogging torque. In order to implement the method, first the expression of cogging torque is studied based on the Fourier analysis. An analytical expression is then introduced based on Permanent Magnet Shifting to reduce cogging torque of LSPMS motors. The method is applied to some existing machine designs and their performances are obtained using Finite Element Analysis (FEA). The effect of magnet shifting on pole mmf (magneto motive force) distribution in air gap is discussed. The side effects of magnet shifting on back-EMF, core losses and torque profile distortion are taken into account in this investigation. Finally the experimental results on two prototypes 24 slot 4 pole inset LSPMS motors have been used to validate the theoretical analysis.

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“…In the last decades, the problem has been identified and widely studied (Gonzales et al, 2007;Zhu et al, 2008;). It has been applied a variety of techniques and methods to reduce a detrimental effect of cogging torque in PM motors (Bianchini et al, 2012;Hanselman, 1994;Levin et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Analysis of the stator topology impact on cogging torque for surface permanent magnet motor

Petkovska

Cvetkovski

Lefley

2015

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering

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Purpose -The paper investigates the impact of the stator core design for a surface permanent magnet (SPM) motor on the cogging torque profile. The objective is to show how the cogging torque of this type of motor can be significantly reduced by implementing an original compound technique by skewing stator slots and inserting wedges in the slot openings.Design/methodology/approach -At the beginning generic model of a SPMM is studied. By using FEA, for this idealised assembly, characteristics of cogging and electromagnetic torque are simulated and determined for one period of their change. Afterwards, actual stator design of the original SPMM is described. It is thoroughly investigated and the torque characteristics are compared with the generic ones. While the static torque is slightly decreased, the peak cogging torque is almost doubled and the curve exhibits an uneven profile. The first method for cogging torque reduction is skewing the stator stack. The second technique is to insert wedges of SMC in the slot openings. By using 2D and 2 1/2D numerical experiment cogging curves are calculated and compared. The best results are achieved by combining the two techniques. The comparative analyses of the motor models show the advantages of the proposed novel stator topology.Findings -It is presented how the peak cogging torque can be substantially decreased due to changes in the stator topology. The constraint is to keep the same stator lamination. By skewing stator stack for one slot pitch 10 deg. the peak cogging torque is 3 fold reduced. The SMC wedges in slot opening decrease the peak cogging almost 4 times. The novel stator topology, a combination of the former ones, leads to peak cogging of respectable 0.182 Nm, which is reduced for 7.45 times.Originality/value -The paper presents an original compound technique for cogging torque reduction, by combining the stator stack skewing and inserting SMC wedges in the slot openings.

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Review of Design Solutions for Internal Permanent-Magnet Machines Cogging Torque Reduction

Cited by 75 publications

References 21 publications

Techniques for Reduction of the Cogging Torque in Claw Pole Machines with SMC Cores

Techniques for Reduction of the Cogging Torque in Claw Pole Machines with SMC Cores

Cogging Torque Reduction in Line Start Permanent Magnet Synchronous Motor

Analysis of the stator topology impact on cogging torque for surface permanent magnet motor

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