Cogging Torque Minimisation of PM Disc Motor by Inserting Stator Slot Closure and Magnet Skewing (original) (raw)
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Progress In Electromagnetics Research B, 2015
This paper deals with the magnet pole shape design for the minimization of cogging torque in permanent magnet synchronous machines (PMSM). New shapes of permanent magnet are proposed. The magnet shape is modeled analytically by a set of stacked and well dimensioned layers relatively to the height and opening angle. The final shape of magnet is configured by using three models in view of obtaining lower magnitude of cogging torque. A 2-D exact analytical solution of magnetic field distribution taking into account the shape of magnet, the irregular mechanical thickness of air-gap and semi-closed stator slots is established. The influence of motor's parameters such as the number of stator slots per pole and per phase and PM's magnetization on cogging torque is discussed. Analytical results are validated by the static finite-element method (FEM).
Industry Applications Conference, …, 2003
A variety of techniques exist for reducing the cogging torque of conventional radial flux PM machines. Even though some of these techniques can be applied to axial flux machines, manufacturing cost is especially high due to the unique construction of the axial flux machine stator. Consequently, new low cost techniques are desirable for use with axial flux PM machines. This paper introduces a new cogging torque minimization technique for axial flux multiple rotor surface magnet PM motors. First, basic principles of the new technique are explored in this paper. A 3-kW, 8-pole axial flux surfacemagnet disc type machine with double-rotor-single-stator is then designed and optimized in order to apply the proposed new method. Optimization of the adjacent magnet pole-arc which results in minimum cogging torque as well as assessment of the effect on the maximum available torque using 3D Finite Element Analysis (FEA) is investigated. The minimized cogging torque is compared with several existing actual machine data and some important conclusions are drawn.
Design Consideration to Reduce Cogging Torque in Axial Flux Permanent-Magnet Machines
IEEE Transactions on Magnetics, 2000
In designing new topologies for permanent-magnet machines based on rare earth magnets, it is necessary to diminish the undesired cogging torque. This paper presents a 3-D finite-element analysis to evaluate the effect of magnet shape and stator displacement on cogging torque reduction, for axial flux machines. It analyzes the final electromagnetic torque for the proposed configurations. Finally, it presents the resultant cogging torque waveform for a 5.0 kW prototype, based on our optimization techniques.
Performance characteristics improvement of a PM disk motor by using soft magnetic composite material
International Journal of Applied Electromagnetics and Mechanics, 2002
The paper presents a comparison of the magnetic field and magnetic characteristics of a PM disk motor with laminated magnetic stator open slot core, laminated magnetic stator closed slot core with soft magnetic composite and soft magnetic composite stator core. The data for this analysis is provided by a 2D FEM calculation of the magnetic field. After the proper modelling of the motor a calculation of the magnetic field for no load and current load is performed, for the three models. The results of the magnetic field distribution, air gap flux density distribution and the values of the magnetic and electric parameters for the three models are also presented.
The Effect of Magnet Structure on the Cogging Torque Reduction in a Permanent Magnet Generator
Journal of Southwest Jiaotong University, 2021
The cogging torque would still be a constant part of permanent magnet-electric machines. This happens because of the construction in which permanent magnets are attached to the rotor, and a slot is present at the core of the stator. The contact between the two, related to the distance between the magnetic surface and the stator slot, makes it challenging to eliminate the cogging torque. This study aims to maximize cogging torque by reducing it with a new method. The proposed method is a mixture of two techniques that indicate significant promise. This invention mixes two techniques to improve the final results. The first process is called magnetic edge shaping, and the second technique is called a dummy slot on the stator. A fractional slot number (FSN) type with 24 slots and 18 poles is the permanent magnet machine used for this investigation. This work is assisted by software version 4.2 of the Finite Element Magnetic Method (FEMM), which will simulate the original and the propose...
Shaping the Stator Poles of BLDCPM Motor for Cogging Torque Reduction
Przeglad Elektrotechniczny
Recently, the cogging torque in electric motors has been drastically decreased as designers and manufacturers have developed better understanding of the cogging phenomenon. The paper presents a design methodology for cogging torque reduction by an appropriate shaping of stator poles in a Brushless DC Permanent Magnet (BLDCPM) Motor. Cogging torque waveforms, along with other relevant characteristics are examined and a new stator poles design of the BLDCPM motor is proposed. Streszczenie. W artykule przedstawiono metodę projektowania bezszczotkowej maszyny DC z magnesami trwałymi (BLDCPM), z uwzględnieniem redukcji momentu zaczepowego poprzez odpowiednie ukształtowanie biegunów stojana. Analizie poddano charakterystyki samego momentu zaczepowego jak i innych, powiązanych z zagadnieniem parametrów. Zaproponowano także nowy projekt maszyny BLDCPM. (Wpływ ukształtowania biegunów stojana na redukcję momentu zaczepowego w maszynie BLDCPM).
Cogging Torque Reduction in Permanent Magnet Machines
IEEE Transactions on Industry Applications, 2007
This paper examines two methods-magnet shifting and optimizing the magnet pole arc-for reducing cogging torque in permanent magnet machines. The methods were applied to existing machine designs and their performance was calculated using finite-element analysis (FEA). Prototypes of the machine designs were constructed and experimental results obtained. It is shown that the FEA predicted the cogging torque to be nearly eliminated using the two methods. However, there was some residual cogging in the prototypes due to manufacturing difficulties. In both methods, the back electromotive force was improved by reducing harmonics while preserving the magnitude.
Progress in Electromagnetics Research M, 2015
So far, several methods to reduce the cogging torque of permanent magnet motors have been introduced. Implementation and evaluation of these methods have usually been done on radial flux types of motors. Nowadays, as axial flux permanent magnet motors have more advantages over radial ones, they are more attractive. Therefore, in this paper analytical modeling and calculation of the most effective method impact in reducing the cogging torque in axial flux permanent magnet motors will be studied. In fact, in this method the radial edges of the magnets will be curved to have a significant impact on reducing this unwanted component. This paper introduces a new concept to model this method. Finally, the accuracy of the proposed method will be verified by finite element analysis.