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This paper presents a FEM-based analysis of two permanent magnet fractional slot machines that have the same stator structure with 9 slots but a different number of rotor poles, which is 8 and 10 respectively. The results have to point out the advantages and drawbacks of each structure. Specific electromagnetic quantities have been investigated such as flux density and back emf, but also cogging torque...
The cogging torque is usually very sensitive to the manufacturing tolerances during machine mass production, and this paper investigates the different sensitivities between interior permanent magnet (IPM) machines with different slot/pole number combinations. Exemplified by two typical combinations, i.e. 12-slot/8-pole and 12-slot/10-pole designs, the fundamental performance is firstly analyzed under...
We are aiming to develop a high precision micro-milling machine with a high speed spindle which is driven by a permanent magnet motor and supported by active magnetic bearings. The torque ripple, however, has influence on the positioning accuracy. As a first step of this study, we investigate torque ripple reduction of a permanent magnet motor. This paper considers optimal winding arrangement of a...
This paper presents the design considerations in cogging torque minimization in two types of transverse flux machines. The machines have a double stator-single rotor configuration with flux concentrating ferrite magnets. One of the machines has pole windings across each leg of an E-Core stator. Another machine has quasi-U-shaped stator cores and a ring winding. The flux in the stator back iron is...
Stator DC winding Excited Vernier Reluctance Machines (DC-VRMs) are a kind of novel machines, which are investigated more and more owing to absence of expensive permanent magnet material. However, DC-VRMs are found to have large torque ripple if they are not carefully designed. There are a lot of existing methods to reduce the cogging torque in permanent magnet (PM) machines, but the design techniques...
Transverse flux machines can be a torque dense solution for applications requiring a relatively low speed such as electrically assisted bicycles or scooters. Common drawbacks include a high torque ripple caused by a high cogging torque and high back electromotive force harmonics. Cogging torque is of particular importance as it can be felt even when the system is disengaged and the bicycle is being...
Torque characteristics, such as torque ripple and average torque, are of particular importance and primary concern during the design stage of permanent magnet synchronous machines for many high-performance applications. Thus, various design techniques have been developed and implemented to improve the torque characteristics in permanent magnet synchronous machines. The impacts of rotor step skewing...
This paper presents a method of reducing the cogging torque of transverse flux machines by shaping the poles of the rotor. A number of different techniques are presented and simulated. These simulations are verified by the construction of a number of rotors from which measured results have been obtained. Further to this, the rotors are applied to machines with different cogging torque reduction techniques...
This research provides a detailed analysis of build variations for mass produced permanent magnet synchronous motors on key performances such as torque ripple, and back-emf harmonics. The study defines the rule for worst case scenarios hence provide tolerance limits for each of the design parameters to be controlled to achieve certain performances under volume production. The research also sorts out...
The rotor shaping methods are frequently used to reduce the cogging torque in interior permanent magnet (IPM) machines. This paper investigates the influence of manufacturing tolerances on cogging torque in IPM machines with eccentric and sinusoidal rotor contours. First, two 12-slot/8-pole IPM machine models are established and the fundamental performance under ideal conditions is presented. Then,...
This paper proposes a rotor tooth shaping method to reduce the cogging torque of an axial flux-switching permanent magnet machine. The rotor tooth is shaped in different configurations, including constant, trapezoidal, asymmetrical, extended, and square shapes. 3-D finite element analysis is performed to compare the proposed shapes of rotor tooth. Peak-to-peak cogging torque, fundamental flux linkage,...
Due to the nature of doubly salient structure and high air-gap flux density, flux-switching permanent magnet (FSPM) machines typically suffer from large cogging torque, causing undesired acoustic noise and vibration, especially at low speeds. In this paper, various tooth chamfering methods for a 12/10 FSPM machine are proposed to reduce cogging torque. The influences of both circular bead and right...
In this paper, a novel flux reversal machine (FRM) is proposed to achieve a larger torque density and a smoother torque waveform than the conventional FRM. The proposed FRM have the same combinations of stator and rotor slots, winding pole pair and PM usage, but different PM arrangement with the conventional FRM, i.e. in the conventional FRM, a pair of PMs is mounted on the surface of each stator...
Recently, outer-rotor electric machine become a research attention to be applied for in-wheel motor either in electric or hybrid electric vehicles (EVs). Among the competitor for in-wheel machines, the permanent magnet synchronous machine (PMSMs) with an outer-rotor have been used widely due to their high performances in terms of torque ad power. However, there is drawback cause by demagnetization...
Interior permanent magnet (IPM) motors become popular and commonly used in industry and domestic applications. One of them is spoke-type IPM. Spoke-type interior permanent magnet (IPM) machines are an attractive topology for high-performance electric motors. In most of the applications, the high strength of permanent magnets causes the undesirable effects of high cogging torque that can aggravate...
Plug-in hybrid electric vehicle (PHEV) is independent of the internal combustion engine but acts as the auxiliary unit mostly on the electric drive system. Main while, the Flux-switching permanent magnet machine (FSPMM) has been studied in terms of structure with its operation principle been analyzed. To achieve a higher torque with a corresponding high power density and lower torque ripple, FSPMM...
The paper presents the concept and results of simulation and experimental research of a claw pole generator with hybrid excitation. Hybrid excitation is performed with a conventional coil located between two parts of the claw-shape rotor and additional permanent magnets which are placed on claw poles. Within the research first a simulation and next constructed experimental model has been developed...
Results of using fractional order PI current controller, and classical one, in case of cogging effect in servo drive are presented in the paper. The general cascade control system of the servo drive and motor model with dry friction are presented. The most significant result in case of using fractional order current controller (FOCC) observed for starting servo drive in the presence of cogging moment...
Ordinary plane existing noncircular gear algorithm has many kinds, but non-circular bevel gear because of its special structure research is not much, this paper deeply studies the similarities and differences of ordinary non-circular gear with non-circular bevel gear, a plane non-circular gear algorithm compatible approximation algorithm for non-circular bevel gear, the core idea of the algorithm...
Radial flux PMBLDC motors are designed using CAD program. CAD program gives dimensions and performance of the motor and compared with finite element analysis result to validate the design. Radial flux PMBLDC motor having only one major disadvantage that is cogging torque. Cogging torque cause due to interaction between magnet and stator teeth that lead to noise and vibration in motor. In this paper...
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