• Journal of Power Electronics
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• v.14 no.5
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• pp.852-858
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• 2014

A novel 12/10 axial field switched reluctance motor (AF-SRM) is proposed for cooling fan applications in this paper. Unlike from conventional structures, the proposed motor uses the axial field instead of the radio field, the rotor is constructed from a series of discrete segments, and the stator poles are constructed from two types of stator poles: exciting and auxiliary poles. This concept improves the torque capability of a previous design by reducing the copper volume, which leads to a higher efficiency. To verify the proposed structure, the finite element method (FEM) and Matlab-Simulink are employed to get characteristics of the proposed SRM. Finally, a prototype of the proposed motor was tested for characteristic comparisons.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.342-344
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• 1999

This paper presents the analysis of core losses in capacitor-run single phase induction motors using the finite element methods. The double revolving field theory can be used for the analysis to assess the quantitative and qualitative performance of the single-phase induction motor. But it is difficult to evaluate accurately the core losses. It is more difficult to segregate stator and rotor core losses at no-load and load conditions. Numerical analysis such as FEM can be used effectively for the accurate calculation of core losses and motors performances. In this paper, the coupling method of core loss characteristic equation and FEM are proposed for the accurate calculation of core losses in the stator and rotor. The FFT is also used to calculate fundamental and harmonic components in the yoke and teeth parts of motor.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.39-40
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• 2014

In this paper, a novel 12/8 segmental rotor type switched reluctance motor (SRM) is proposed. Different from conventional structures, the proposed rotor consists of a series of discrete segments, and the stator is constructed from two types of stator poles: exciting and auxiliary poles. Moreover, in this structure short flux paths are taken and no flux reverse exists in the stator. While the auxiliary poles are not wound by the windings, which only provide the flux return path. Compared with conventional 12/8 SRM, the proposed structure increases the electrical utilization of the machine and decreases the core losses, which may lead to high efficiency. To verify the proposed structure, finite element method (FEM) is employed to get static and dynamic characteristics. Finally, a prototype of the proposed motor is tested for characteristics comparisons.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.11
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• pp.1528-1534
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• 2013

This paper proposes the optimal design of stator shape for cogging torque reduction of single-phase brushless DC (BLDC) motor with asymmetric notch. This method applied size and position of asymmetric notches to tapered teeth of stator for single-phase BLDC motor. Which affects the variation of the residual flux density of the permanent magnet. The process of optimal design included the extraction of the sampling point by using Latin Hypercube Sampling(LHS), and involved the creation of an approximation model by using kriging method. Also, the optimum point of the design variables were discovered by using the Genetic Algorithm(GA). Finite element analysis was used to calculate the characteristics analysis and cogging torque. As a result of finite element analysis, cogging torque were reduced approximately 39.2% lower than initial model. Also experimental result were approximately 38.5% lower than initial model. The period and magnitude of the cogging torque were similar to the results of FEA.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2274-2277
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• 2003

A cylindrical permanent magnet inside the four-phase permanent magnet (PM) stepping motor is employed as the rotor. The stator has four teeth around, which its coils are wound. The mode of excitation can be classified into 3 modes: single-phase excitation, two-phase excitation and ministep excitation. The ministep drive is a method to subdivide one step into several small steps by means of electronics. The paper presents the programmable ministep technique drive. This technique decodes the results obtained from the counter to locate the data in Read Only Memory (ROM). The Sinusoidal Pulse Width Modulation (SPWM) is transformed to binary file and saved to the ROM. The experiment is performed with the four-phase PM stepping motor and drives from a two-phase programmable sinusoidal ministep signal, instead of square wave. The results show that the performances of the proposed programmable ministep technique drive have high efficiency, smooth step motion, and high speed response. Moreover, the resolution of sinusoidal ministep signal can be controlled by the input frequency (f command).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1568-1574
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• 2017

This paper studied cogging torque reduction effect for sloping notch applied two notches on stator teeth. We have confirmed accuracy of FEM(Finite Element Method) through comparison previous model using asymmetric notch for experiment and 3D FEM results, and then cogging torque comparison of previous model and sloping notch model. Also the sloping notch model has been modified to step-sloping notch model to consider manufactur. The modification method of sloping notch changed the degree of slope of notch (a)(Notch(a) sloping Deg) and the degree of Slope of notch (b)(Notch(b) Sloping Deg). When Cogging torque is case of minimum, Notch (a) Sloping Deg is $-12[^{\circ}]$ and Notch(b) Sloping Deg $12[^{\circ}]$. In this case, cogging torque was about 23.9[mNm]. Cogging torque of previous model is about 40.8[mNm], so sloping notch model is less than previous model by 41.42[%]. Also, if sloping notch model is changed to step-sloping notch model, cogging torque of step-sloping notch model is about 24.82[mNm], Therefore the difference between the two cogging torque is about 3.85[%], so step-sloping notch model can be applied when considering manufacture.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.95-99
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• 2005

This paper presents a general proposal to design and calculate the performance of a tubular permanent magnet linear generator treated here on the basis of the Finite Element Method. Optimizing the linear generator dimensions reduces the cogging force, which occurs due to the interaction between stator teeth and the permanent magnets. The generated AC voltage is analyzed and evaluated for both no load and load cases to take the armature reaction effects on the air gap flux density. A repetitive routine is followed to calculate the output AC voltage from the change of flux and the speed of the single-phase linear generator. The AC output voltage is calculated for different resistive loads, and hence, the linear generator load characteristic is obtained. The designed linear generator is capable to generate an output power of 5.3kW with AC output voltage of 222V with an efficiency of 96.8% at full load of 23.8A. The full load current is chosen based on the thermal properties of the coil wire insulations.