• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.781-782
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• 2006

This paper presents a drive strategy to reduce torque ripple of a permanent magnet Brushless DC Motor(BLDCM) with short $120^{\circ}$ flat top Back Electromotive Force(Back-EMF). In this strategy, the phase Back-EMF is divided into four sections. Then, in each section the phase current is regulated by corresponding PWM duty ratio to compensatethe torque ripple caused by imperfect Back-EMF. A program based on this strategy has been implemented in MATLAB@Simulink. The validity of the presented method is verified by simulation results.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.6
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• pp.982-990
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• 1994

In this paper, we consider feedback-kinearizing control of brushless dc motors which have been increasingly used in high-performance servo applications, We completely characterize the whole class of the feedback controllers that enable the brushless dc motors to behave like linear systems but without torque ripple. The whole class of the feedback-linearizing controllers is characterized in the explicit form which contains a function to be chosen freely. The previously known controllers correspond to either the particular ones in our whole class of the feedback-Linearzing controllers or their truncated Fourier expansions. This free function can be used to achieve other control objectives as well as linear dynamic characteristics. Furthermore, our feedback-linearizing controllers can be easily determined from the measurement data of back EMF.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.27-31
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• 2010

Torque ripple of the motor used in EPS raises vibration problem on steering system. To solve this problem, this paper proposes a optimum design for torque ripple reduction of Surface-mounted Permanent Magnet Synchronous Motor(SPMSM) in EPS. Through analyis back-EMF using Finite element method as changing the shape of permanent magnet and stator shoe, we presented the method of torque ripple redution.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1108-1110
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• 2000

The BLDCM(Brushless DC motor) has been the Trapezoidal Back Electromotive Force(EMF) due to a surface magnet rotor with nonlinear distribution and full-pitch windings. Theoretically, it should be fed with rectangular phase current in order to minimize torque ripple. But, because voltage source inverter drives BLDCM, perfectly rectangular phase currents are not available. Now in this paper, using fourier series coefficients, calculating the coefficients of harmonic current within available orders and each harmonic component are controlled on stationary frame. Only using four switches, low cost and small size drive can be made and proposed method will be more useful in industrial. Simulation and experimental results prove the validity of the proposed method.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1093-1095
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• 2000

In this paper, describes a rotor speed identification method of induction motor based on the theory of counter EMF MRAS. This method eliminated the pure integrator and we can be expected to rapid responsibility of the speed identification. Therefore, we may improve the initial condition of the integrator and drift problem. The stability of speed estimator is proved on the basis of hyperstability theory. In order to confirm the performance of the proposed system, simulation and experiment is performed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.5
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• pp.660-665
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• 2014

This paper presents the improved back-EMF of Interior Permanent Magnet Synchronous Generator(IPMSM) for small hydropower generator. To improve back-EMF characteristics, the size and position of notch are applied to the rotor. In addition, parametric analysis of the notch size and position was performed. Finally, the back-EMF characteristic analysis are confirmed by the experimental results.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.9
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• pp.454-459
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• 2003

Conventional integral-slot design in permanent magnet(PM) motor tends to have a high cogging torque and large end turns, which contribute to copper losses. The fractional-slot design is effective compared to integral-slot design in the cogging torque and electromotive force(EMF) waveform. The effectiveness of fractional slot can be maximized by selecting optimal pole to slot ratio. This paper presents the effect of pole to slot ratio on the cogging torque and EMF waveform in the PM motor with fractional-slot. The effectiveness of the proposed designs has been confirmed by comparing waveform of EMF. cogging torque and torque ripple between conventional and new models.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.100-102
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• 2009

밴드패스필터를 사용하여 센서리스 벡터제어에 영향을 주는 6차고조파 성분을 제거하여 안정적인 제어를 제안하였다. 비정현적인 역기전력을 가진 IPMSM모터의 센서리스 벡터 제어에서 유기전압에 고조파가 포함되는 경우에 그 영향이 추정연산에 나타나게 된다. 삼상 모델에 나타나는 5차, 7차 고조파의 경우는 d, q축 모델로 변환 시 6차 고조파 성분으로 나타나게 된다. 이 6차 고조파 성분은 위치 추정과 속도추정에 영향을 주어서 토크 맥동을 발생시킨다. 본 논문에서는 이러한 6차 고조파의 영향으로 추정연산에 미치는 영향들을 알아보고. 이 영향을 고조파 제거를 위한 복잡한 계산을 하지 않으면서 간단한 밴드패스필터를 통해 고조파가 위치추정에 미치는 영향을 최대한 줄이는 방법을 제시하였다.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.186-188
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• 2005

BLDC 전동기는 선형적인 토크 대 전류, 속도 대 전압 특성을 갖고 있으며 기계적, 전기적인 잡음이 없고, 가감속 제어가 용이하며, 토크 대 관성의 비가 매우 높아 소형으로 높은 출력을 낼 수 있다는 장점을 가지고 있다. 그러나 전기자 전류의 전환(Commutation)시 고정자 권선의 인덕턴스 성분과 역기전력으로 인해 발생되는 전류 리플은 BLDC 전동기 토크리플의 중요한 원인이 된다. 이에 본 논문에서는 고속 연산이 가능하고 별도의 외부 메모리 없이 칩 하나로 모든 동작을 할 수 있는 TMS320LF2407 DSP칩을 사용, Hard-chopping PWM 방식을 이용하여 전류 리플을 감소시켰으며, 이를 시뮬레이션 및 실험을 통해 증명하였다.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1050-1052
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• 2005

In this paper, air gap flux density is calculated by permeance model which can consider the effects of the stator slot and the salient pole shape of the salient synchronous generator. No load Electro-motive force(EMF) of the short-pitched and distributed stator winding is also calculated. Therefore, it's very convenient to calculate the THD of the no load EMF for the user's request, in the first design state.