An Optimal Method for Minimizing Cogging Torque in Disc-Type Permanent Magnet Machines Using FEM and Genetic Algorithm

2013 ◽  
Vol 416-417 ◽  
pp. 21-26
Author(s):  
Jing Shi Shangguan ◽  
Cheng Zhi Fan
Keyword(s):  
Genetic Algorithm ◽  
Permanent Magnet ◽  
Permanent Magnet Machines ◽  
Optimal Method ◽  
Cogging Torque ◽  
Slot Opening ◽  
The Impact

Cogging torque is one of the main reasons which cause ripple in motor's speed and torque. So the reduction of cogging torque must be considered in the design of permanent magnet machines. There are many existing techniques for reducing cogging torque in PM machines. This paper presents a new optimal method for cogging torque minimization by magnet shifting in disc-type PM machines. The impact of magnet shifting on cogging torque and torque output are discussed in disc-type PM machines. In order to reduce the cogging torque effectively while without being harmful to the average torque output. This paper used genetic algorithm (GA) to calculate the shift positions combined with slot-opening optimization to achieve the minimum cogging torque.

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

2015 ◽  
Vol 34 (2) ◽  
pp. 456-474 ◽  
Author(s):  
Lidija Petkovska ◽  
Goga Cvetkovski ◽  
Paul Lefley
Keyword(s):  
Permanent Magnet ◽  
Generic Model ◽  
The Novel ◽  
Permanent Magnet Motor ◽  
Stator Core ◽  
Cogging Torque ◽  
Content Type ◽  
Slot Opening ◽  
The Impact ◽  
Static Torque

Purpose – The purpose of this paper is to investigate the impact of the stator core design for a surface permanent magnet motor (SPMM) 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° the peak cogging torque is threefold reduced. The SMC wedges in slot opening decrease the peak cogging almost four 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.

Cogging Torque Reduction by Slot-Opening Shift for Permanent Magnet Machines

2013 ◽  
Vol 49 (7) ◽  
pp. 4028-4031 ◽  
Author(s):  
Ting Liu ◽  
Shoudao Huang ◽  
Jian Gao ◽  
Kaiyuan Lu
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnet Machines ◽  
Cogging Torque ◽  
Slot Opening

scholarly journals Improving a Cogging Torque Reduction Technique for Fractional Slot Numbers in a Permanent Magnet Machine

2020 ◽  
Vol 55 (6) ◽  
Author(s):  
Tajuddin Nur ◽  
Marsul Siregar ◽  
O.B.W. Sandra ◽  
Karel O. Bachri
Keyword(s):  
Permanent Magnet ◽  
Air Gap ◽  
Reduction Technique ◽  
Permanent Magnet Machines ◽  
Permanent Magnet Machine ◽  
Cogging Torque ◽  
Slot Opening ◽  
Rotor Core ◽  
Simulation Results ◽  
Machine Structure

For this paper, an improvement to a cogging torque reduction technique was studied in regards to integral slot numbers in a permanent magnet machine. An 18 slot/8 pole permanent magnet machine structure was selected and developed, and some axial channels were introduced to the machine’s rotor core. The effects the axial channels had on cogging torque reduction were not studied in detail; however, it was noted that the channels did not disturb the machine’s normal magnetic flux in regards to an air gap. Two slotting steps were used on the edge of the machine’s permanent magnet with slot opening widths of 2 mm and air gap lengths of 1 mm; this was done in order to minimize cogging torque. Three different magnet structures for the permanent magnet machine were then analyzed and compared. The two steps for slotting were found to be best for cogging torque reduction among the three different structures. Finally, simulation results showed that improving slotting steps for magnet edges could significantly reduce cogging torque in permanent magnet machines by up to 98.80%.

A New Method for Minimizing Cogging Torque in Permanent Magnet Machines Using Genetic Algorithm

2013 ◽  
Vol 690-693 ◽  
pp. 2693-2698
Author(s):  
Jing Shi Shangguan ◽  
Cheng Zhi Fan
Keyword(s):  
Genetic Algorithm ◽  
Finite Element Method ◽  
Finite Element ◽  
Permanent Magnet ◽  
New Method ◽  
Permanent Magnet Machines ◽  
Cogging Torque ◽  
Element Method

Cogging torque is one of the main reasons which cause ripple in motor's speed and torque. So the reduction of cogging torque must be considered in the design of permanent magnet machines. This paper presents a new method for cogging torque minimization by optimizing pole-arcs combined with varying the thickness in magnets. With the combination of different pole-arcs of each PM slice to achieve the minimum cogging torque while without being harmful to the average torque. Thus, optimize the offset value which varies the thickness of magnets to further reduce the amplitude of cogging torque. In this paper, it used genetic algorithm (GA) to optimize pole-arcs and magnet offset on the basis of Finite Element Method (FEM).

scholarly journals A Design Method for the Cogging Torque Minimization of Permanent Magnet Machines with a Segmented Stator Core Based on ANN Surrogate Models

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1880
Author(s):  
Elia Brescia ◽  
Donatello Costantino ◽  
Paolo Roberto Massenio ◽  
Vito Giuseppe Monopoli ◽  
Francesco Cupertino ◽  
...  
Keyword(s):  
Finite Element ◽  
Permanent Magnet ◽  
Design Method ◽  
Heuristic Approach ◽  
Topological Optimization ◽  
Permanent Magnet Machines ◽  
Stator Core ◽  
Cogging Torque ◽  
Design Formula ◽  
Harmonic Components

Permanent magnet machines with segmented stator cores are affected by additional harmonic components of the cogging torque which cannot be minimized by conventional methods adopted for one-piece stator machines. In this study, a novel approach is proposed to minimize the cogging torque of such machines. This approach is based on the design of multiple independent shapes of the tooth tips through a topological optimization. Theoretical studies define a design formula that allows to choose the number of independent shapes to be designed, based on the number of stator core segments. Moreover, a computationally-efficient heuristic approach based on genetic algorithms and artificial neural network-based surrogate models solves the topological optimization and finds the optimal tooth tips shapes. Simulation studies with the finite element method validates the design formula and the effectiveness of the proposed method in suppressing the additional harmonic components. Moreover, a comparison with a conventional heuristic approach based on a genetic algorithm directly coupled to finite element analysis assesses the superiority of the proposed approach. Finally, a sensitivity analysis on assembling and manufacturing tolerances proves the robustness of the proposed design method.

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