• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.2
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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.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.9
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• pp.490-497
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• 1999

This paper presents a novel current control method to reduce the current ripple due to commutation in brushless DC motor fed with unipolar PWM voltage source inverter. The proposed current control method can reduce the current ripple due to commutation in high speed range where the DC link voltage of the inverter is less than four times of the phase back-emf. The effectiveness of the proposed current control method is verified with digital simulations and experiments on the 250W brushless DC motor drive systems.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.1
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• pp.101-109
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• 2000

Mutual torque ripple in a brushless DC motor is the main source of acoustic noise, especially fur motor operation with high speed and torque. This paper presents a method to obtain mutual torque ripple to identify acoustic noise source. Mutual torque ripple can be determined by analyzing phase current shape and magnetic circuit with different lead angles. Current shape is determined by state space model of voltage equation with the use of inductance calculated by FEM, and confirmed by experimental results. Mutual torque ripple is also determined by FEM analysis for the calculated current shape. Acoustic noise experiment reveals that mutual torque ripple with different lead angle is one of the main sources for noise generation in a brushless DC motor.

• 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.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.843-845
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• 2001

In this paper, we analyze the characteristics of electecromotive force(emf), phase current and torque according to the length of the air gap using 2nd order FEM(Finite Element Method) in Synchronous Reluctance Motor(SRH) and Brushless DC Motor(BLDC) with same volume and size. In the analysis with FEM, we applied the time-step function considering the motor switch in the magnetic vector potential of the unknown node.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.6-8
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• 2004

Recently, it is increasing to use more Brushless DC Motor with high energy density permanent magnet and semiconductor control unit for complementing the mechanical defect of Brushed DC Motors. For designing of BLDC Motors are required complex parameters like as rated characteristic, Geometries, B-H curve of magnet and steel materials, winding factor, etc. Moreover, design and manufacturing are difficult because of additional control circuits. Generally, Design parameters are gotten by analysis of Motor which is used. And the design parameters are used to design a new motor. But getting the design parameters through the eyes and experience is limited and it takes a long time. In this paper a method is proposed to efficiently analyze motor design parameters through the No load and Load Test, Back EMF Test, Simulation Analysis and Patent Analysis Method for existing BLDC Motor for a cooling Fan in Vehicle.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.8
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• pp.183-192
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• 1998

In this paper, we measure the back-EMF and the thrust of a linear brushless DC motor along the relative position between coils and magnets in various speed environments in order to obtain the back-EMF and the thrust as a function of a motor position. The measured back-EMF function and thrust function of the position differ from the analytical ones within 5%. The measured back-EMF and thrust function can, then, be employed in controlling the thrust ripple of the linear motor. Furthermore, to minimize the torque ripple of the linear motor, we suggest the design method to shape the back-EMF and thrust function of the linear motor.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.7 no.2
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• pp.41-50
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• 1993

This paper describes an effort to develop a microcomputer-based parameter identification system for three phase and two phase brushless DC motor. Back EMF equation is derived from back EMF waveform of three phase and two phase brushless DC motor. In this paper, a new identification algorithm for the brushless DC motor parameters by Pasek's technique is developed. It is found that Pasek's equation is valid for the brushless DC motor, too. The results obtained clearly shows that it is possible to implement the identification system for the determination of the brushless DC motor parameters. To minimize errors due to the ripple component in the measured armature current, digital averaging firis employed. The whole identification process of signal generation, measuring, parameter determination is fully automated. The use of the propod method in the parameter identifition system shows that the averaged current curve is in excellent agreement with the estimated current curve. Therefore, this close agreement confirms the validity of this technique.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.379-381
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• 1999

This paper presents a study of the performance of a brushless DC motor (BLDCM) speed control system. Recently, most motor controls are implemented in digital electronics. Digital controllers tend to be more accurate, less susceptible to noise and more flexible in terms of programming. The system used a digital PI controller in order to implement the constant speed of Brushless DC motor. Microprocessor used in this experiment is 80c196kc. The applied motor has been constructed using a 50W, 150V, 3000rpm, four-pole motor.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.3
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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.