• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.76-80
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• 2011

This paper proposes a method to calculate magnetostrictive forces, displacement, and vibration modes of a large-scale Brushless DC(BLDC) motor by using a magneto-mechanically strong coupling formulation. The force is calculated using the energy method with magnetostrictive stress tensor. The mechanical vibration modes are also analyzed by using the principle of Hamilton and the calculated magneto-elastic forces acting on the surfaces of the stator. To verify the algorithm, 3 MW BLDC motor is simulated, and the forces, displacements, and vibration modes are calculated. The result shows that the mechanically stressed core has more deformation or displacements than those of the normal condition.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.5
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• pp.222-230
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• 2005

This paper deals with the reduction of cogging torque of a outer-rotor type BLDC motor mainly used for washing machines. The motor comprises permanent magnet outer-rotor and stator with coils and core. This structure inherently produces vibration and cogging torque because of uneven reluctance according to rotation of the rotor. Up to now, adopted a type of 24 magnet pole and 36 slot-stator. This generates high main torque but accompanies comparatively large cogging torque. This paper proposes a 32-pole 36-slot type motor which reduces cogging torque remarkably. The influence of cogging torque is varied according to pole-slot combinations. The characteristic of the motor was obtained by a two-dimensional finite element method coupled with a drive circuit. The performance of the proposed model is superior to that of the existing model because of the reduction of torque ripple and the improvement of back ernf wave form.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.702_703
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• 2009

Electric Power Steering(EPS) system is superior to conventional Hydraulic Power Steering(HPS) system in aspect of fuel economy and environmental concerns. The EPS system consists of torque sensor, electric motor, ECU(Electric Control Unit), gears and etc. Among the elements, the torque sensor is one of the core technologies of which output signal is used for main input of EPS controller. Usually, the torque sensor has used torsion bar to transform torsion angle into torque. The torsion angle of both ends of a torsion bar is measured by a contact variable resistor. In this paper, the sensor is accurately analyzed using 3D finite element method and its characteristics with respect to four different shapes of the stator teeth are compared. The four shapes are rectangular, triangular, trapezoidal and circular type.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.31-33
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• 2007

Cost reduction requires lowering number of power devices used in the converter driving SRM. This is quite feasible in SRM drive systems than in other drive systems. This paper deals with design, analysis, and simulation of such a novel two phase SRM. A novel two phase SRM has high performance, self-starting capability, high efficiency, and low manufacturing cost. Additionally, the stator back iron does not experience any flux reversal as the flux is in the same direction whether phase A or B is excited leading to a greater reduction in core losses. The magnetic analysis and design considerations of the novel two phase SRM have been obtained by the finite element analysis (FEM). Experimental verification of the machine design is provided to correlate with analysis and simulation studies.

• Journal of Magnetics
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• v.17 no.4
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• pp.285-290
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• 2012

Electric Power Steering (EPS) system is superior to conventional Hydraulic Power Steering (HPS) system in aspect of fuel economy and environmental concerns. The EPS system consists of torque sensor, electric motor, ECU (Electric Control Unit), gears and etc. Among the elements, the torque sensor is one of the core technologies of which output signal is used for main input of EPS controller. Usually, the torque sensor has used torsion bar to transform torsion angle into torque and needs linear characteristic in terms of flux variation with respect to rotation angle of permanent magnet. The torsion angle of both ends of a torsion bar is measured by a contact variable resistor. In this paper, the sensor is accurately analyzed using 3D finite element method and its characteristics with respect to four different shapes of the stator teeth are compared. The four shapes are rectangular, triangular, trapezoidal and circular type.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.4 s.235
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• pp.518-525
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• 2005

The electromagnetic noise generates when natural frequencies of a stator core with wingdings and frame coincide with or approach natural frequencies of the magnetic motive force. In order to suppress such noise, the estimation of natural frequencies of the motor is important at the design stage. However, the natural frequency analysis is not so easy because motor stator is in the laminated plate structure and windings are composed of wires, insulation sheets and vanishs. Thus the accurate prediction of the equivalent material properties of windings becomes an essential task. In this paper, we derive the equivalent material properties using homogenization methods.

• Journal of the Korean Society of Safety
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• v.15 no.4
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• pp.56-61
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• 2000

The precise and reliable loss model for induction motor and converter system is very important in order to predict the efficiency performance of variable speed drives. This paper proposes an accurate loss model of induction motor and converter system. The motor losses, such as stator and rotor copper loss, core loss and stray loss, are considered for fundamental and harmonic frequencies. Also considered are the skin effect on rotor resistance, temperature effect on bath stator and rotor resistance, magnetizing inductance saturation, and friction and windage loss. All the above features are incorporated in a synchronous frame dynamic d-q equivalent circuit. The converter system, consisting of a diode rectifier and PWM transistor inverter, is modeled accurately for conduction and switching losses. Validity of the models, in both steady state and transient conditions, is verified by simulations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.152-155
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• 2002

During normal operation, partial discharge(PD) tests were performed using turbine generator analyzer(TGA) in high voltage motor. Epoxy-mica couplers are installed at motor terminal and analyzed PD signal using TGA. #A motor stator insulation is good because small partial discharges are detected PD pattern show that PD occurs in insulation. PD of #B motor is larger than that of #A motor and PD pattern show that positive PD larger than negative PD. It means that PD occurs between insulation and slot. And A phase PD magnitude of #B motor is large and high compare with any other phase. Therefore wedge, core and slot of #B motor need to check and repair.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.199-202
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• 2002

During normal operation, partial discharge(PD) tests were performed using turbine generator analyzer(TGA) in high voltage motor. Epoxy-mica couplers are installed at motor terminal and analyzed PD signal using TGA. #A motor stator insulation is good because small partial discharges are detected. PD pattern show that PD occurs in insulation. PD of #B motor is larger than that of #A motor and PD pattern show that positive PD larger than negative PD. It means that PD occurs between insulation and slot. And A phase PD magnitude of #B motor is large and high compare with any other phase. Therefore wedge, core and slot of #B motor need to check and repair.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.4
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• pp.145-151
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• 1999

This paper presents the characteristic analysis method of PMLSM based on the Space Harmonic Analysis method considering the effect of stator slots. The magnetic field for unslotted primary can be easily calculated by the conventional space harmonic analysis method and the resultant magnetic field including slot effect is obtained using the concept of the virtual Equivalent Magnetizing Current(EMC) on primary core. And the influence of space harmonics in airgap flux density and static thrust due to slots is evaluated. In this paper, the results of the analytical method are compared with not only the experimental ones but ones of FEM to verify the validity of the proposed method.