• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.714-716
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• 2003

This paper deals with the characteristic analysis of a brushless DC motor (BLDC) and taking into consideration the freewheeling diodes and DC link voltage ripple using a time-stepped voltage source finite element method. By comparing with the experimental results, we show that the proposed computational method is useful for the analysis and design of a BLDC motor. We also examine the influence of freewheeling diodes and DC link voltage ripples on the performance of a BLDC motor such as torque ripples and radial force on the surface of the teeth.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.2
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• pp.164-170
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• 2010

In brushless DC motor, current flow should be controlled such that only properly selected 2 out of 3 phases carry current depending on the position of rotor. In order to detect position of rotor, hole sensor, encoder, optical position-detecting sensor, and magnetic position-detecting sensor are frequently employed. These sensors not only often cause malfunction in low and high temperature but they also have disadvantage of increasing cost and size of an motor system. To reduce the cost and size and to increase the robustness of the motor system, recently researches on sensorless motor dirve are very active. This paper proposes a novel unipolar PWM switching method that can improve the control problem caused by the difficulty of detecting zero crossing point at high revolution speed by minimizing the switching noise while increasing the lifespan of the drive system.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.5 no.3
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• pp.54-63
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• 1991

This paper describes an effort to develope a microcomputer-based parameter measurement system for a brushless DC motor. Back EMF equation is derived from back EMF waveform of a brushless DC motor. To minimize error the due to the ripple component in the measured armature current, digital averaging filter is employed. The whole identification process of signal generation, measurement parameter determination is fully automated. A new identification algorithm for the brushless DC motor parameters is developed. New parameter correction method is proposed using the deadzone current and the time to reach the peak current. In the proposed correction method, the measured current is in excellent agreement with the estimated current.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.8
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• pp.71-78
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• 2012

Recently, it is increased to apply sensorless drive for BLDC (Brushless DC) motor to maximize operating efficiency and fuel efficiency to an electrical component of (H)EV. Especially, Electric vehicle component promotes a fuel efficiency enhancement by the carbon dioxide emissions regulation of a vehicle becoming the principal of the environmental pollution globally, the oil price hike that continued increasingly. We suggested the air compressor which applied BLDC motor for electric vehicle component and compared suggested BLDC motor with the conventional DC motor. The experimental results show that the driving efficiency was increased and was inproved compressive force by suggested BLDC motor.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.6
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• pp.278-286
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• 2005

Recently, high-speed centrifugal turbo-compressors have been under intensive research and development. Since, compared to conventional compressors, high-speed centrifugal compressors hive numerous qualities such as simple structure, light weight small size, and high efficiency, etc. In cope with such industrial demands, a high-speed brushless DC motor for a 50-kW, 70-krpm turbo-compressor was developed based on a 2-D analytical method, of which design was verified using the FE analysis. A prototype machine was also fabricated and tested to confirm the analytical design. Preliminarily obtained experimental data using the prototype mac]line shows the validity of the analytical approach.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.6
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• pp.939-945
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• 2009

This paper is described BLDC motor in the submarine propulsion system which is asked high power per unit area. This study analyzes the independent 6-phase BLDC motor a specific extended by existing the independent 3-phase BLDC motor and propose forward development direction. Independent 6-phase motor has a characteristics that phases of stator are independent electrically with each other and two's independence 3-phase BLDC motor are linked with each difference of 60 degree. Six-phase BLDC motor is simulated with Matlab-simulink, the simulation result has a high current and low torque pulsation than existent independence 3-phase BLDC motor.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.51-52
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• 2016

본 논문은 속도 운전 영역 확장을 위한 자동 진상각 제어 알고리즘을 제안한다. 속도 운전 영역 확장을 위하여 상전류의 위상을 역기전력의 위상에 대하여 진상으로 제어한다. 기존의 진상각 제어 방식은 속도 - 진상각 참조표를 이용하거나 추가적인 하드웨어를 구성하여 제어한다. 참조표를 이용한 제어 방식의 경우 전동기의 특성에 매우 민감하며 운전점이 변경될 경우 제어 특성이 현저히 나빠지는 단점이 있으며, 추가적인 하드웨어를 이용하는 경우 전동기의 제정수에 의존적임과 동시에 제어 시스템의 부피 및 비용 증가와 같은 문제를 야기시킨다. 본 논문은 유효 전압의 크기와 전류 제어기의 궤환 전압을 이용하여 필요한 진상각을 계산한다. 본 논문에서 제안하는 방식의 유용함은 컴퓨터 시뮬레이션을 통하여 타당함을 검증하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.95-102
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• 2014

This paper presents zero crossing point(ZCP) estimation methods considering discretization error for a high speed brushless DC(BLDC) motor drive. The ZCP is estimated by detecting the change of back-EMF polarity for the BLDC sensorless drive, and the discretization error exist on the estimated ZCP. The discretization error of the ZCP is a cause of the delay of a commutation timing of current and increment of a current ripple factor. Besides a delay of a ZCP estimation brings on the limitation of a speed range for the BLDC sensorless drive. The compensation method based on the error analysis with probability theory for reducing the effects of the discretization error of the ZCP is proposed. Also a ZCP estimation method according to the Back-EMF patterns is proposed to widen the speed range for the BLDC sensorless drive. The proposed methods are verified by the experiment.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.5
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• pp.325-331
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• 2004

The multiobjective optimization (MO) problem usually includes the conflicting objectives and the use of conventional optimization algorithms for MO problem does not so good approach to obtain an effective optimal solution. In this paper, genetic algorithm (GA) as an effective method is used to solve such MO problem of brushless DC motor (BLDCM). 3D equivalent magnetic circuit network (EMCN) method which enables us to reduce the computational burden is also used to consider the 3D structure of BLDCM. In order to effectively obtain a set of Pareto optimal solutions in MO problem, ranking method proposed by Fonseca is applied. The objective functions are decrease of cogging torque and increase of torque respectively. The airgap length, teeth width and magnetization angle of PM are selected for the design variables. The experimental results are also shown to confirm the validity of the optimization results.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.475-478
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• 1994

In this paper two methods of torque control for brushless DC motor with non-ideal trapezoidal back EMF are presented. One is the method of modulating the reference current so as to give a constant torque since the torque is given by the back EMF and the. phase currents. And the current control loop includes the feedforward control of back EMF and of the neutral voltage between the neutral points of the inverter and of the machine. The other is a direct voltage calculation algorithm for a given reference torque. In the two methods, the time delay due to the calculation is compensated by one sampling current prediction. The simulation results are presented to verify the proposed methods.