• Journal of the Korean Magnetics Society
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• v.26 no.3
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• pp.86-91
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• 2016

The cogging torque of a brushless dc (BLDC) motor results from the interaction between permanent magnets and iron core, and it causes noise and induce vibrations. During a manufacturing process, assembly tolerances lead to the change of the electromagnetic structure of a BLDC motor where permanent magnets are not properly glued to the surface of rotor core. In this paper, the effect of magnet separation from the surface of rotor core on the cogging torque is investigated due to assembly tolerance. The relationship with key design parameters is considered such as separation between magnets and rotor core, the number of magnets having separation, as well as the several types of arrangements among neighboring magnets. Finite element method (FEM) has been used to analyze a BLDC motor, and the allowable assembly tolerance is proposed to prevent generating noise and vibrations. Within proposed assembly tolerance, it is concluded that the cogging torque of a BLDC motor is decreased, and hence noise and vibrations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.4
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• pp.812-818
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• 2003

This paper presents a developed outside rotor type induction motor for the fan. Nearly all of the induction motors consist of two parts, rotor and stator, and the position of rotor is generally inside of stator. However, the rotor of the developed induction motor is located outside of stator. It is believed that the outside rotor type induction motor is suitable for the fan due to its large inertia, that is, it is considered that the change of air flow rate resulting from input power or load fluctuation is reduced. In this paper, the two tests which are suitable to obtain the electrical parameters of the outside rotor type induction motor were described, then various parameters of outside rotor type induction motor were measured. These are the locked rotor test and no load test. By using these tests, it was possible to determine the parameters which are presented in the steady-state equivalent-circuit of the outside rotor type induction motor. Load test of induction motor was carried out using a dynamometer and the torque-speed curve was obtained. It is believed that the results of this paper can be used for the development of the outside rotor type induction motor.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.4
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• pp.423-429
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• 2013

The performance of a vertical-type wind power generator system was predicted by CFD analysis. In the analysis, the reaction torque was calculated for a given rotational speed of the blades. The blade torque of a wind power system was obtained for various rotational speeds, and the generation power was calculated using the obtained torque and the rotational speed. The optimum generator specification, therefore, could be decided using the relationship between the generated power and the rotational speeds. The effects of the number of blades and blade shapes on the generation power were also investigated. Finally, the analysis results were compared with the experimental results.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.10a
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• pp.201-204
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• 2004

감속기가 사용되어지는 경우 부하의 변동이나 구동부의 상태변화에 따라 모터의 토크, 회전수 등이 변하는데 이러한 값들을 모니터링 하면 부하의 변동이나 구동부를 진단할 수 있다. 본 논문은 유성기어를 이용한 기어드 모터를 제작하고, LCD를 포함하는 간단한 사용자 인터페이스를 통해 전달 Torque, 전달회전수(rpm), 전달동력을 확인할 수 있는 소형의 표시기가 있는 감속기에 관한 것이다. 일반적으로 전달 토크를 측정하는 장비는 크기가 크고 고가이며 계측기를 연결하고 측정하는 과정이 매우 번거로울 뿐만 아니라 지속적인 유지보수가 필요한 단점이 있다. 본 논문에서 제안하는 유성기어를 사용하면 간단히 모터의 토크 및 회전수를 측정할 수 있고 측정값을 표시하는 표시기를 모터에 부착할 수 있다. 측정 및 표시기는 기존 가격에 비해 매우 값싸게 제작할 수 있고 유지보수가 필요 없으며 검출 값을 시스템 제어부에 피드백 시키면 자기진단이 가능해진다. 특히 블루투스를 이용한 무선 통신기능을 부과하면 원격 모니터링이 가능하고 복수 모터유닛의 네트워크 구성이 용이하며 인터넷을 통한 데이터 통신으로의 확장이 가능하다.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1065-1070
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• 2017

Magnetic gears are magnetically coupled to the input side and the output side of the rotary machine to transmit power without mechanical contact. The magnetic gear consists of an inner rotor, an outer rotor and pole pieces. Torque ripple occurs due to the difference in reluctance between the two rotors and the pole pieces during power transmission. Torque ripple is a cause of the noise and vibration of the rotary machine, so it is necessary to minimize it. In this paper, we propose a shape that cuts the corner of the pole piece and apply a fillet to reduce torque ripple. We used a two-dimensional finite element analysis method to compare and analyze the torque ripple of the magnetic gears according to the change of the fillet parameters and to find the pole piece shape with excellent torque ripple.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.133-138
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• 2016

Force control and collision detection for a robot are usually conducted using a 6-axis force/torque sensor mounted at the end-effector. However, this scheme suffers from high-cost and the inability to detect collisions at the robot body. As an alternative, joint torque sensors embedded in each joint were used, which also suffered from various errors in torque measurement. To resolve this problem, a robot joint module with an improved joint torque sensor is proposed in this study. In the proposed torque sensor, a cross-roller bearing and disk-type coupling are added to prevent the moment load from adversely affecting the measurement of the joint torque under consideration. This joint design also aims to reduce the stress induced during the assembly process of the sensor. The performance of the proposed joint torque sensor was verified through various experiments.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.441-442
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• 2020

본 논문에서는 2상 하이브리드 스테핑 모터의 디텐트 토크 보상 기법을 제안하였다. 2상 하이브리드 스테핑 모터의 회전자 좌표계 d,q축 전압 방정식 및 토크 식으로부터 지령 토크 발생을 위해 필요한 d,q축 전류를 지령으로 사용하며, 디텐트 토크로 인해 발생하는 속도 리플을 제거하기 위해 리플 크기를 추출하여 전류지령에 보상하였다. Matlab/Simulink를 이용한 2상 하이브리드 스테핑 모터 구동 시뮬레이션을 통해 제안된 기법의 유효성을 확인하였다.

• 대한공업교육학회지
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• v.33 no.2
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• pp.218-231
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• 2008

The purpose of this study was made for the pre-teacher of university to enhance understanding for the concept of engine performance and to provide information regarding engine performance in the institute of teacher educator. This study was carried out through engine performance experiment with The Cussons Engine Test Bed P8250, internal combustion engine, in order to analyze data quantitatively, and apply and verify factors of controlling engine performance. The main results of this study are as follows: First, power and brake horsepower increased linearly, and torque over the mid-speed as engine rps(revolution per second) decreased. Second, the change of torque and specific fuel consumption were able to be verified and the concept of engine performance was able to be understood. Third, the experimental values of brake horsepower and torque on engine performance showed the same tendency as theoretical values. Fourth, air/fuel ratio increased proportionally as engine speed increased.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.44-45
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• 2013

본 논문은 3상 PMSM 동작 중 한 개의 상이 고장이 났을 경우, 2상을 통하여 고장허용 동작을 하는데 있어서 발생하는 토크 리플 저감 방법에 대하여 연구를 하였다. 기존의 방법들이 기본파 주파수로 회전하는 동기좌표계상에서 전향 보상 방식으로 교류 성분의 전류를 제어함으로써 토크 리플을 보상하는 데에 반해 제안한 방법은 기본파 주파수의 2배수로 회전하는 동기좌표계상에서 직류 성분의 전류로 토크 리플을 보상하기 때문에, 저속 운전뿐만 아니라 고속 운전시에도 그 보상 특성이 매우 우수하다. 제안한 방법은 자동차용 전동식 조향 시스템에 적용하여 그 유효성을 실험적으로 검증하였다.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2365-2372
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• 2011

The Cogging Torgue is non-uniform torgue in motor which causes noise and vibration to synchronous motors such as BLDC motor, and regardless of load current, is generated by the interaction between permanent magnet rotor and stator slot which is the force of tangential direction that tends to move into the position where the magnetic energy of motor system is minimal. such Cogging Torgue shall be considered in design stage since it is the main factor of motor's noise and vibration. Understanding that Cogging Torgue is generated by the interaction between relatively low stage harmonic flux density gab of permanent magnet rotor and steel slot of stator. This study proposes the method if reducing Cogging Torgue using response surface method which is a kind of design if experiment.