• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.6
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• pp.730-737
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• 2018

This paper aims to design of a double stator axial field 12/10 SRM. Conventional and single stator axial field SRMs were reviewed to apply for automotive cooling fan. The axial field SRM has the advantage of shorter flux path, higher torque per volume and lower iron loss. However, there is axial eccentricity in single stator axial field SRM due to one side excitation. Therefore, a double stator type is designed in this paper to reduce the axial eccentricity. And the trapezoidal pole shape of the stator increases the flow of magnetic flux from stator to rotor and the torque region. The torque and efficiency are compared and tested with experiments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.746-752
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• 2011

In this paper, a novel bearingless switched reluctance motor (BLSRM) with double stator is proposed. This motor has two stators. Torque stator is outside, which mainly produces rotational torque. Radial force stator is inside, which mainly generates radial force to suspend the rotor. A novel structure and operating principle are presented. And characteristics of the proposed structure such as magnetic flux distribution, inductance, torque and radial force are analyzed through finite element method. From the analysis, the proposed BLSRM has linear characteristic of radial force and independence from torque current.

• Journal of Electrical Engineering and Technology
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• v.9 no.4
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• pp.1315-1323
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• 2014

Although the power density in Double Stator Switched Reluctance Motor (DSSRM) has been improved, the torque ripple is still very high. So, it is important to reduce the torque ripple for specific applications such as Electric Vehicles (EVs). In This paper, an effective rotor shaping optimization technique for torque ripple reduction of DSSRM is presented. This method leads to the lower torque pulsation without significant reduction in the average torque. The method is based on shape optimization of the rotor using Finite Element Method and Taguchi's optimization method for rotor reshaping for redistribution of the flux so that the phase inductance profile has smoother variation as the rotor poles move into alignment with excited stator poles. To check on new design robustness, mechanical analysis was used to evaluate structural conformity against local electromagnetic forces which cause vibration and deformation. The results show that this shape optimization technique has profound effect on the torque ripple reduction.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.4
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• pp.379-382
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• 2014

In this paper, the cogging torques were calculated for 1kw double-sided axial flux permanent magnet (AFPM) generator with different stator core pole arrangements. The generator is composed of 18 stator pole and 24 rotating field magnets on each side. The cogging torques of the generator with three types of arrangements of stator poles were calculated using 3D finite element method and the optimum core shape was determined to minimize the cogging torque.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.2
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• pp.71-77
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• 2012

The cogging torque is important to the cut-in wind speed. And, it causes the acoustic noise and the vibration on the machine. This paper presents a 3D FEA(Finite Element Analysis) to evaluate the effect of magnet skew and stator displacement on cogging torque reduction, for double core AFPM(Axial Flux Permanent Magnet) generator. As a result, the magnet skew and the stator side displacement are proved excellent techniques to reduce the cogging torque.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.766-772
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• 2013

Modeling and control of radial force in the double stator type bearingless switched reluctance motor (BLSRM) is researched. The rotational torque is controlled independently from the radial force control. And the radial force is constant which is independent from the rotor position. In order to realize steady suspension, analytical models of torque and radial force for the proposed structure are derived. Meanwhile, in order to realize steady suspension, control scheme for proposed BLSRM is proposed. In the control method, the radial force can be controlled in arbitrary direction and magnitude by selecting some combinations of radial force windings. The validities of structure and control method are verified by the experimental results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.131-141
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• 2016

SRM is designed to meet operating standards such as low cost, simple magnetic structure, a desired operating speed range, high efficiency, high performance, and good matching for DC power. The magnetic flux of SRM is independent of its direction to develop a torque and it allows the flexible characteristics of the magnetic structure for SRM. In this paper, SRM can widely classify two types, Radial-Flux SRM and Axial-Flux SRM, according to the flux direction. Radial-Flux SRM includes Conventional, Segmented stator and rotor, and Double stator SRM, etc. and Axial-Flux SRM includes C-core stator and the Axial-airgap SRM. This paper is subjected the basic characteristics to select the best of the magnetic structure of SRM in the appropriate application by the classification of SRM.

• Journal of Electrical Engineering and Technology
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• v.11 no.5
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• pp.1475-1485
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• 2016

• Journal of Power Electronics
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• v.9 no.1
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• pp.109-116
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• 2009

This paper addresses the output control of a utility-connected double-fed induction machine (DFIM) for wind power generation systems (WPGS). DFIM has a back-to-back converter to control outputs of DFIM driven by the wind turbine for WPGS. To supply commercially the power of WPGS to the grid without any problems related to power quality, the real and reactive powers (PQ) at the stator side of DFIM are strictly controlled at the required level, which in this paper is realized with the Fuzzy PI controller based on the field orientation control. For the Sinusoidal Pulse Width Modulation (SPWM) converter connected to the rotor side of DFIG to maintain the controllability of PQ at the state side of DFIM, the DC voltage of the DC link capacitor is also controlled at a certain level with the conventional Proportion-Integral (PI) controller of the real power. In addition, the power quality at the grid connected to the rotor side of DFIM through the back-to-back converter is maintained in a certain level with a PI controller of the reactive power. The controllers for the PQ at the stator side of DFIM, the DC link voltage of the back-to-back inverter and the reactive power at the grid connected to the rotor side of DFIM are designed and simulated in the PSIM program, of which the result verifies the performance of the proposed controllers.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2158-2167
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• 2018

This paper analyzed the magnetic field produced by the cylindrical stator coils of permanent magnet spherical motor (PMSM). The elliptic equations about the vector magnetic potential were given. Given that the eddy current effects are neglected, the magnet field of the PMSM is regarded as irrotational field, which can be calculated by scalar magnetic potential. The current density of cylindrical stator coil was proposed based on the definition of current density. The expression of current density of stator coil was obtained according to the double Fourier series decomposition and spherical harmonic functions. Then the magnetic flux density for scalar magnetic potential was derived. Further, the influence of different parameters on radial flux density was also analyzed. Finally, the results by the analytical method in this paper were validated by finite element analysis (FEA).