• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2095-2097
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• 1997

This paper describes a indirect sensing method for the rotor flux position of interior permanent magnet (IPM) brushless DC motors. The phase inductance of an IPM motor varies appreciably according to the rotor position. The waveform characteristics of the terminal voltage of IPM brushless DC motors is analysed and a simple and practical method for indirect sensing of the rotor position is proposed. A compact sensorless drive is implemented and tested using a 87c196mc 16-bit microcomputer. The experimental results show the validity of the proposed method and the drive works well from 500 to 7,200rpm.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.599-601
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• 2001

This paper investigates the permanent magnet (PM) overhang effect on the characteristics such as cogging torque and torque in brushless DC motor (BLDCM). The overhang effect has been used to enlarge the performance of the radial flux density in BLDCM and balance the force in the axial direction for the reduction of the vibration. 3D equivalent magnetic circuit network method (3D EMCNM) is used for the accurate and efficient analysis. The characteristics of BLDCM are analyzed according to the variation of overhang length and the optimal length and ratio of overhang is determined.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.641-643
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• 2002

Synchronous generator needs slip-ring and brush for supplying current to rotor with external source. but slip-ring and brush have some problems to supply DC power to field winding with friction and high power loss due to brush voltage drop at high field current. Thus synchronous generator have been designed to brushless machine. Brushless synchronous machines of using permanent halbach array can composed without back core and coreloss. In this paper, analyse on the characteristics of external rotor type permenant magnet brushless with halbach array.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.9
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• pp.1234-1239
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• 2013

This paper provides a technical review of speed control using variable gain PI algorithm for BLDC(Brushless DC) motor. Usually the PI control is used in many motor applications, but a general PI control has problems of overshooting and disturbance for response. By the change of PI gain in motor control operation, these problems can be solved. To find the optimized PI gains for BLDC motor control, many control methods have been proposed. In this paper, the control algorithm with a variable PI gain is applied to improve overshooting response in transient region and rapid load disturbance rejection. Fixed gain and variable gain PI controls are compared. The validity of the propose method is verified by experiment.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.10
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• pp.646-651
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• 2000

Recently, the 2-phase brushless DC motor has been used in electric home appliance for low price and low energy consumption. In this paper, we analyzed a 2-phase BLDC motor using time-step finite element method. And the validity of analysis is confirmed by measuring the flux distribution on the surface of permanent magnet and back-EMF. As well, we have calculated the dynamic characteristics of target motor considering the Hall sensor position. So, we have found the optimum switching position, and improved performance of 2-phase BLDC motor.

• Journal of Magnetics
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• v.20 no.1
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• pp.91-96
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• 2015

As many researchers are relentlessly trying to improve the power generation schemes from the power grid, to meet the constantly increasing electricity demand. In this paper, the results of a finite element analysis are carried out to study on a design optimization of an asymmetric air-gap structure in 3-phase Permanent Magnet Brushless DC Motors. To achieve a high efficiency for a 3-phase PM BLDC motor, the asymmetric air-gap structure is proposed considering the rotation direction of a motor. Generally, a single-phase BLDC motor is applied asymmetric air-gap structure for starting. This is because the asymmetric air-gap structure causes reluctance variation so the motor can utilize reluctance torque toward a rotation direction. In this paper, the asymmetric air-gap is applied to 3-phase BLDC SPM motor so it utilizes reluctance torque with alignment torque. A proposed model is designed by 2-D FE analysis and the results are verified by experimental test.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.766_767
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• 2009

Generally, the Doubly Salient Machine such as Switched Reluctance Motor doesn't have Permanent Magnet, it sometimes adopts permanent magnet or DC filed winding for high efficiency or adjustable speed control. In this paper, adjustable speed range is compared for Doubly Salient Permanent Magnet Machine (DSPM), Brushless Doubly Fed Doubly Salient Machine (BDFDS) and Hybrid Excited Doubly Salient Machine (HEDS). Especially, air-gap flux density to the DC field current is shown and the operating speed as the field-weakening is estimated.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.924-926
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• 2001

This paper presents the characteristics of current harmonics and torque ripple of Brushless DC motor, which is developed the fan blower of vehicles, according to permanent magnet shape input voltage wave form. To investigate the torque ripple and the phase current harmonics, these characteristics is analysed and compared the experimental results. In the process of analysis, FEM is introduced and computed a transient state torque of BLDC with a sinusoidal and a PWM wave voltage.

• Journal of Power Electronics
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• v.7 no.2
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• pp.132-139
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• 2007

Electrical motors are an integral part of industrial plants with no less than 5 billion motors built world wide every year. The demand for low-cost brushless DC (BLDC) motors has increased in industrial applications. This paper presents a BLDC motor control algorithm for low-cost motor drive applications using general purpose microcontrollers which have only one on-chip timer. This paper describes how to realize pulse width modulation (PWM) signals with general input/output (I/O) ports to control a three-phase permanent magnet brushless DC motor using the timer interrupt on MSP430F1232.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.7
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• pp.346-352
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• 2006

In Brushless DC Motor, there are Permanent Magnets (PMs) with driving circuit and sensor for detecting to rotor position and rotation speed. In the case of using hall IC sensor which response to magnetic flux, that is required to additional sensor magnet for rotor position detecting. Most of BLDC motor, However, take asymmetrical overhang of PM in rotor instead of additional sensor magnet for operating of hall IC sensor. The asymmetrical overhang of PM occur rotor thrust to z-axis direction that is lead to not only damage of bearing but also intensive noise and vibration. Therefore, the analysis of magnet overhang effect in the side of vibration and drive to hall If sensor is required to precise. In this paper, 2-D Finite Element Method is used to solve precise field computation and thrust of z-axis direction considering asymmetrical magnet overhang. And also the z-axis thrust from the analysis result is compared to experimental result. In conclusion, the purpose of this paper minimize to noise and vibration of BLDC Motor as analyzes to asymmetrical magnet overhang effect.