• 대한전기학회논문지
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• 제43권6호
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• pp.885-895
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• 1994

In this paper, we propose the one-Ampere conductor method which is able to calculate the flux distribution conceptually and easily, and the improved winding method which suppresses space harmonics of magnetormotive force and enhances the coefficient of utilization of primary iron core in tubular linear induction motor. We carry out no-load test to verify effectiveness of proposed method and analyze characteristics by finite element method. As a result, performances are improved and propriety of primary iron core is enhanced comparing with conventional model.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제11B권2호
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• pp.1-8
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• 2001

This paper deals with magnetic field analysis and computation of cogging torque using an analytical method in Interior Permanent Magnet Motor (IPMM). The magnetic field is analyzed by solving space harmonics field analysis due to magnetizing and the cogging torque is analyzed by combining field analysis with relative permeance. In reducing cogging torque, the inferences of various design variable and magnetizing distribution are investigated. It is shown that the slot and pole ratio (the pole-arc / pole-pitch ratio) combination has a significant effect on the cogging torque and presents a optimal flux barrier shape to reduce the cogging torque. The validity of the proposed technique is confirmed with 2-D Finite Element(FE) analysis.

• 한국조명전기설비학회지:조명전기설비
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• 제6권6호
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• pp.32-41
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• 1992

In this paper, an advanced Pulse Width Modulation Inverter strategy for driving a variable-speed induction motor is introduced. A switching pattern making use of the near-proportionality of voltage and frequency in AC machines operating with constant flux was computed. At low magnitudes and ow frequencies of the fundamental, many more harmonics are eliminated than at high magnitudes and frequencies. In order to keep the inverter switching frequency constant over the output frequency range, the chopping frequency is diminished as the frequency of the fundamental increases. Using these modulation strategy, the harmonics components of PWM inverter are efficiently eliminated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.171-173
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• 1995

Slot field harmonics exist in air gap due to inevitable slot constructure of induction motors. They give rise to noise by the electromagnetic vibration and mechanical pulsation. We calculate the slot field harmonics for varying the ratio of slot width vs teeth pitch using the carter's coefficent. We computate the flux density in air gap by FEM(Finite Element Method) and analyze it in frequency domain using DFT(Discrete Fourier Transform). We develop the new algorithm mixing FEM with DFT.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 연구회 합동 학술발표회 논문집
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• pp.64-67
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• 1998

This paper proposes the hybrid PWM scheme that can obtain less harmonic characteristics in GTO inverters. By employing the variable of the dc-link voltage Vdc, the hybrid PWM pattern can ideally compensate the dc input fluctuation together with selected harmonics elimination. The transient behavior, which the magnetic flux and torque are altered and the large current flows instantly, may be produced when the mode change. To reduce such an undesirable transient behavior, it is also presented the technique for the gear changing of inverter operated with the hybrid PWM. The results are verified by simulations and experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.67-69
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• 2002

This paper present increasing of Power density of slotless PMLSM by inserting core between phase winding. PM width is changed and PM is divided into two part to reduce and eliminate high order space harmonics affecting torque ripple. Flux density, back EMF, inductance, thrust, normal and detent force are computed by 2D FEM, and analysis values are compared with each other.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2027-2034
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• 2008

To predict efficiency of Interior Permanent Magnet Synchronous Motors(IPMSM) and to cope with the demagnetization risk of permanent magnets used in the IPMSM, accurate iron analysis of the IPMSM is very important at the motor design stage. In this paper, we present the method to estimate the iron loss for the IPMSM considering the condition of field weakening control and harmonics of flux density waveform.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1996년도 창립기념 전력전자학술발표회 논문집
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• pp.13-16
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• 1996

A new instantaneous torque control technique is presented for a high performance control of a permanent magnet synchronous motor. Using the model reference adaptive system technique, the linkage flux of the motor is estimated and the torque is instantaneously controlled by the proposed torque controller combining with a variable structure control and space vector PWM. The proposed torque control provides the advantage of reducing the torque pulsation caused by the flux harmonics. This control strategy is applied to the high torque PM synchronous motor drives for direct drive systems and is implemented by using a software of the DSP TMS320C30. The experiments are carried out for this system and the results well demonstrate the effectiveness of the proposed control.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.804_805
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• 2009

This paper deals with analysis on electromagnetic characteristics of linear induction motor(LIM) using the analytical method. As a analytical method, space harmonics method which is applied to multilayer region is used in this paper. Using the flux density obtained by analytical method, thrust and normal force are calculated through Maxell stress tensor. The results such as flux densitty, eddy current and force are verified by comparison between analytical results and FEM.

• Journal of Magnetics
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• 제19권4호
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• pp.393-398
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• 2014

This paper proposes new types of models that have coaxial magnetic gear (CMG) configurations to increase torque transmission capability. They have flux concentrating structures at the outer low speed rotor, and permanent magnets (PMs) are embedded in the space between stationary pole pieces. The torque performances of the proposed models are compared with those of a basic CMG model. The harmonic torque components due to air gap field harmonics are also analyzed to investigate the torque contribution of each harmonic by using finite element analysis (FEA) and the Maxwell stress tensor. The proposed CMG model is optimized to have high torque density with low torque ripples by response surface methodology (RSM). Compared to the basic CMG model, the proposed model has a huge increase in transmitted torque density, and is very advantageous in term of PM use.