• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.48-53
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• 2014

Generally, the usage motor in the vehicle is exposed to highly ambient temperature and large vibration according to repeatedly starting and stopping during very short time. So, in this paper, the rotor shape design was performed to improve demagnetization endurance by considering starting current of Brushless DC Motor (BLDCM) through Finite Element Method(FEM). As a result, the end of Permanent Magnet (PM) in the basic model was occurring a partial irreversible demagnetization by starting current. To solve this problem, the installing flux barrier was limited to flux line on the core. Accordingly, demagnetization endurance and operating characteristics were improved.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.490-492
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• 1997

This paper describes a digital sensorless drive of permanent magnet brushless DC (PM BLDC) motors. The sensorless drive adopts a digital filter - moving average finite impulse response filter for accurate estimation of commutation time. Experimental results show that the performance of the proposed sensorless drive is superior to that of the sensorless drive without filtering.

• 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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.4
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• pp.735-741
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• 2009

This paper presents an algorithm for the permanent magnet shape optimization of a large scale BLDC(Brushless DC) motor to minimize the cogging torque. A response surface method (RSM) using multiquadric radial basis function is employed to interpolate the objective function in design parameter space. In order to get a reasonable response surface with relatively small number of sampling data points, additional sampling points are added on the basis of design sensitivity analysis computed by using FEM. The algorithm has 2 stages: the first stage is to determine the PM arc angle, and the 2nd stage is to optimize the magnet pole shape. The developed algorithm is applied to a 5MW BLDC motor to get a minimum cogging torque. After 3 iterations with 4 design parameters, the cogging torque is reduced to 13.2% of the initial one.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.336-339
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• 2005

This paper presents a PM type BLDC(Brushless DC) Motor servo drive system using high performance DSP TMS320F2812. The DSP controller with 150MIPS enables an enhanced real time implementation and increased efficiency and high performance for motor drive. The suggested drive system consists of PI action for the constant speed control and PID action for the current control with only 3 Halls, no encoders. The developed servo drive control system shows a good response speed characteristics at high speed up to 10000 [rpm].

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.435-438
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• 2002

The Objects of this paper are developing and also improving a high-speed driving system of bushless DC motor(BLDCM) with economical and practical performance. Because BLDC motors are manufactured that each motor can create proper torque for their individual purpose, it is difficult to increase over the rated speed when a motor speed (with it's rated road) is reaching to a maximum speed so the motor torque cannot be increased. This paper verifies the effects of Leading Angle Algorithm, that is proposed on this paper, with examining existing methods to maximize the torque of a motor in high-speed driving area. The arithmetic processor for this experiment is TMS320C240 DSP controller that is designed for a special purpose of motor control in Texis Instrument Inc., and the used Inverter is PM10CSJ060, a Intelligent Power Module of Mitsubishi Corporation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.9
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• pp.454-461
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• 2001

Acoustic noise and vibration of a BLDC motor is a coupled phenomenon between mechanical characteristics and electromagnetic origins through the motor air-gap. When a relative misalignment of rotor in the air-gap center exists on the assemblage, it is considered to influence the motor system characteristics. In this paper, the back electro motive force(BEMF) is analyzed by Finite Element Method(FEM) and verified by experiments for the SPM and IPM type motors. For magnetic field analysis, a FEM is used to account for the magnetic saturation. Using these results, the FEM is made to determine the appropriate electromagnetic field analysis in BLDC motors with rotor eccentricity ratio. A radial magnetic imbalance force of BLDC motor with rotor eccentricity is analyzed. Results demonstrate that the imbalance force is increased according to the degree of misalignment. An IPM motor, mostly chosen to realize high-speed operation, shows a worse effect on magnetic unbalanced forces and dynamic responses compared with SPM motor due to magnetic saturation when the rotor eccentricity exists.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.3
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• pp.107-114
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• 2001

Electro-mechanical battery (EMB) consists of a high-speed fly wheel with an integral motor/ generator suspended on magnetic bearings and in an evacuated housing. Permanent magnet (PM) machines as the EMB motor/ generator are a popular choice, since there are no excitation losses which means substantial increase in the efficiency. In this paper we present the comparison of conventional slotted and slotless ring-wound types, aimed at EMB and other high-speed drives. We firstly discuss the topology of each machine for this particular application. these machines are primarily designed as 1kW two-pole PM generator with the rated speed of 40000 rpm. the motoring torque of 0.51 Nm has to be enough to accelerate the flywheel to the rated speed. We then present the comparison of the open-circuit field, the armature reaction field and winding inductance. next we analyze the induced voltage and the developed torque per unit stack length and unit weight of different machines. Finally, we estimate and compare the losses and the efficiency at motoring and generating modes.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.337-339
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• 2001

High speed brushless permanent magnet (PM) machines are a key technology for electric drives and motion control systems for many application, since they are conductive to high efficiency, high power density small size and low weight. Proposed slotless PM machine is constructed without stator winding slots. Its stator magnetic material is in the form of a ring and winding have a toroidal configuration and its rotor consists of a 4-pole Halbach array or radially magnetized PM rotor.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.3
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• pp.207-214
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• 2005

After more than 100 years of development, rotating electric machines are a mature industrial product. Nevertheless, improvements are still possible for specific applications, and it is likely that the major evolution will be promoted by new materials and unconventional structures. Till now, plastic materials are an infrequent choice for the electric machines structural parts, but pioneering applications, such as aeronautical components, let some technological scouting: a low-weight/high-efficiency plastic axial flux motor for a solar flying platform is presented as an example of combined new-material/new-geometry development. The basic design aspects and the prototyping choices are presented and discussed together with the first experimental results.