• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.9-11
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• 1996

This paper is dealing with the slotless AFPM(Axial Flux Permanent Magnet) Brushless Motor. It has been reported that AFPM brushless DC motor have high efficiency and high energy density than radial flux permanent brushless DC motor. AFPM brushless DC motor finds its application of electric vehicles. In this paper, small AFPM brushless DC motor was designed using the ferrite permanent magnet. For this design, magnet of rotor, stator dimension and stator winding parameters has been studied and prototype AFPM motor has been assembled and motor speed, torque and efficiency are investigated.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권2호
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• pp.146-153
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• 2005

In a permanent magnet brushless dc motor, cogging torque is produced by the magnetic attraction between the rotor mounted permanent magnets and the stator teeth. This always produces a pulsating torque ripple resulting in vibration and acoustic noise, which is detrimental to the motor performance. This paper deals with the analytical prediction of cogging torque and the various cogging torque minimization techniques as applied to a permanent magnet brushless dc motor.

• 대한전기학회논문지
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• 제35권9호
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• pp.396-402
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• 1986

Although the structure of the brushless DC motor is similar to the one of the permanent magnet synchronous motor, its operating characteristics are the same as those of the permanent magnet DC motor. This is the reason that the commutators and brushes in the permanent magnet DC motor can be replaced by the power semiconductor devices and rotor position sensors for the brushless DC motor. In this paper, a current control method is presented to make a sinusoidal current waveform for constant torque generation and the operating characteristics of the brushless DC motor using the resolver as the rotor position sensor is also presented and experimented.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제4B권3호
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• pp.122-126
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• 2004

The objective of this paper is to provide a comparison between the Line Start Permanent Magnet, Skeleton type Brushless DC, and the Snail-cam type Switched Reluctance Motor. These motors are compared under the same load characteristic as the cooling fan motor of a refrigerator. The comparison consists of speed, output power, efficiency, copper loss, and cost for three different motors. For the given application, the results provide an indication of the best machine suited with respect to performance and cost.

• 전력전자학회논문지
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• 제21권5호
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• pp.449-452
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• 2016

This paper presents a simplified analysis on the rotor position detection error in sensorless interior permanent magnet brushless DC motor (BLDCM) drives, wherein terminal voltage sensing based on the back-electromotive force (back-EMF) zero-crossing point detecting circuitry is employed. The effect of a rotor saliency on the back-EMF's zero-crossing point detection is analyzed using the extended EMF-based voltage equation of the interior permanent BLDCM in a stationary reference frame, and thus the overall analysis is considerably simplified compared to the conventional one. Simulation results are provided to verify the effectiveness of the proposed method.

• 한국자동차공학회논문집
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• 제6권4호
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• pp.39-46
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• 1998

For permanent magnet brushless DC motors used for high speed fuel pumps, torque ripple is an important origin of vibration, acoustic noise and speed fluctuation. In this paper, the output torque profile of a PM motor with one phase energized is decomposed into the commutation torque, the reluctance torque and the armature reaction torque according to their source origins. It verifies that the output torque profile is qualitatively equivalent to the BEMF profile for low reluctance motors. This paper discusses the effect of magnet pole shaping and magnet arc length on the output torque and torque ripple. A magnet edge shaping is proposed to design a trapezoidal BEMF motor without torque ripple, with minimal sacrifice of the maximum output torque.

• 대한전기학회논문지
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• 제37권9호
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• pp.600-608
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• 1988

Although the structure of brushless dc motor is similar to that of a Permanent magnet synchronous motor, its torque-speed characteristcis are the same as those of a permanent magmet dc motor. The brushless dc motor drive systemcomposed of power converter including inverter, rotor positioning sensor and controller has been investigated for the purpose of position control when the motor is fed by a current controlled voltage source inverter. The equivalent transformation of a brushless dc motor into an separately exited dc motor has been possible with the vector control (field oriented control) technique. It is shown in this paper that the position control of a brushless dc mitor can be done fairly accurately only using q-axis current.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.700-702
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• 2002

High-speed brushless permanent magnet machines are good for compressor and aerospace applications, etc. since they are conductive to high efficiency, high power density, small size and low weight. This paper presents 3-phase permanent magnet brushless AC Motor designed for the high-speed drives. Especially, we predicted the inverter high frequency pulse width modulation (PWM) switching caused eddy current losses in a permanent magnet brushless dc motor.

• 한국자동차공학회논문집
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• 제6권2호
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• pp.235-243
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• 1998

For motor operation at low speeds and loads, torque pulsation by the cogging torque is often a source of vibration and control difficulty. In this paper, the magnetic field of a motor is calculated by finite element method. The periodic cogging torque is determined using Maxwell stress method and time stepping method, and then decomposed using fourier series expansion, The purpose of this paper is to characterize design parameters on the cogging torque and to design a permanent magnet motor with a cogging torque less vulnerable to vibration, without sacrificing the motor performance. The design parameters include stator slot width, permanent magnet slot width, airgap length and magnetization direction. A new design with a less populated frequency spectrum of the cogging torque is proposed after characterizing individual effect of design parameters. Magnet pole edge shaping, by gradually increasing the cogging torque with reduced higher harmonics.

• Journal of Magnetics
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• 제18권2호
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• pp.117-124
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• 2013

Single-phase, brushless DC (BLDC) motors have unequal air-gaps to eliminate the dead-point where the developed torque is zero. Unfortunately, these unequal air-gaps can deteriorate the motor characteristics in the cogging torque. This paper proposes a novel design for a single-phase BLDC motor with an asymmetric notch to solve this problem. In the design method, the asymmetric notches were placed on the stator pole face, which affects the change in permanent magnet shape or the residual flux density of the permanent magnet. Parametric analysis was performed to determine the optimal size and position of the asymmetric notch to reduce the cogging torque. Finite element analysis (FEA) was used to calculate the cogging torque. A more than 28% lower cogging torque compared to the initial model with no notch was achieved.