• 전기전자학회논문지
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• 제24권2호
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• pp.441-445
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• 2020

효율 및 제어성이 우수한 영구자석 전동기는 최근 자동차 조향장치 시스템용으로 많이 응용되고 있으며, 인버터 고장 발생 시에도 일정시간 운전이 가능하여 안전성과 신뢰성을 확보할 수 있도록 다양한 형태의 이중 3상 구조의 고정자 권선방법을 적용하고 있다. 본 논문에서는 진상 및 지상의 전류위상 변화 시 각각의 권선방법이 전동기 특성에 미치는 영향을 유한요소해석을 통해 분석하고, 그 결과 이중 3상 고정자 권선을 갖는 동기전동기 설계 시 특성 측면에서 가장 적절한 권선방법을 선정할 수 있도록 설계전략을 제시한다. 구체적으로 토크 및 효율 측면과 약계자 제어를 통한 정출력 영역 확대 측면, 그리고 저진동 및 저소음을 위한 토크 리플 저감 측면에서 각각 유리한 권선방법을 제시한다.

• ETRI Journal
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• 제41권6호
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• pp.838-849
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• 2019

We present a permanent magnet-based spherical wheel motor that can be used in omnidirectional mobility applications. The proposed motor consists of a ball-shaped rotor with a magnetic dipole and a hemispherical shell with circumferential air-core coils attached to the outer surface acting as a stator. Based on the rotational symmetry of the rotor poles and stator coils, we are able to model the rotor poles and stator coils as dipoles. A simple physical model constructed based on a torque model enables fast numerical simulations of motor dynamics. Based on these numerical simulations, we test various control schemes that enable constant-speed rotation along arbitrary axes with small rotational attitude error. Torque analysis reveals that the back electromotive force induced in the coils can be used to construct a control scheme that achieves the desired results. Numerical simulations of trajectories confirm that even without explicit methods for correcting the rotational attitude error, it is possible to drive the motor with a low attitude error (<5°) using the proposed control scheme.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.347-349
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• 1995

This paper describes current controlled PWM technique of IPM synchronous motors for a wide variety of speed control applications. They are however limited in their ability to operate in the power limited regime where the available torque is reduced as the speed is increased above its base value. This paper reviews the operation of the IPMSM drives when they are constrained to be within the permissible envelope of maximum inverter voltage and current to produce the rated power and to provide this with the highest attainable rotor speed. This paper proposes a new field-weakening control algorithm using phase current feedback to improve the torque characteristics and to reduce the torque ripple of IPMSM in the constant power region. The improved torque characteristics of speed control strategy with current feedback control algorithm is analyzed and the performance is investigated by the computer simulation results.

• 한국가시화정보학회지
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• 제22권2호
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• pp.63-73
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• 2024

The injection of polymer can significantly reduce drag, particularly in the turbulent flow region where the mutual interaction between the polymer and turbulent vortices occurs. In this study, Taylor-Couette flow of PEO-in-water solutions with a rotating inner cylinder was analyzed. Despite the shear-thinning behaviour of PEO-in-water solutions being well-documented, for a given range of shear rates their viscosity remains nearly constant. By varying the polymer concentration, we analyzed the torque evolution of different solutions followed by the viscoelasticity effects of the polymer on the interphase transition points. The torque was analyzed using a dimensionless torque scaling method, which allows for the assessment of the fluid's momentum transport capabilities. It was observed that for low concentrations of PEO, the flow behaviour exhibited only minor differences in comparison to that of water, the Newtonian fluid. However, once the PEO concentration exceeded the polymer overlap concentration, the flow behaviour was significantly altered.

• 한국자동차공학회논문집
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• 제16권2호
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• pp.183-190
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• 2008

This paper deals with the characteristics of idle vibration due to the type of constant velocity joints. Based on the kinematics model of constant velocity joints, a offset between the tripod center and tullip center plays a important role in generating unwelcome forces. Moreover, it induced additional forces in lateral direction of a vehicle movement according to the angle of the spider in idle vibration. The difference of mass for each constant velocity joint types affect the natural frequency of the driveshaft and the powertrain. When the static torque is applied to the constant velocity joints, the natural frequencies of the driveshaft are reduced nearby 50Hz. There will be a big opportunity that the dirveshaft and constant velocity joints would be a transfer path of idle vibration at D or R gear range. Experiments indicate that TJ type is better than SFJ and DOJ in idle vibration.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.594-596
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• 1987

In this study, a method of obtaining reasonably large and constant torque at high speed is given in order to improve the performance of the open loop controlled step motor system using the current source, thus resulting in high performance compared to the conventional current limiting using resistor and chopper.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.110-113
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• 2000

In general, speed control method of the elevator system has used motor pole change type or motor primary voltage control type. But it will change to vector control type in order to increase it's reliability, riding comfort and decrease material cost. It is the conception of vector control type in order to increase it's reliability, riding comfort and decrease material cost. It is the conception of vector control that primary current of the induction motor be controlled independently with magnetizing current(field current of DC motor) and torque current(armature current of DC motor). In this paper, by analyzing the effect of the time constant variation of rotor of the induction motor on the slip frequency type indirect vector control, a drive system for the motor will be constructed using a fuzzy slip frequency type indirect vector controller with fuzzy control method for estimating the vector time constant in the slip frequency type indirect vector control. The goal of this study is to enabling even more efficient speed control by constructing on elevator driver based on the newly developed drive system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.950-954
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• 1998

This paper describes a development of traction unit for 2-motor driven electric vehicle (EV). The traction unit is consisted with an interior permanent magnet synchronous motor (IPMSM), a reduction gear and an inverter for electric vehicle that is driven by 2 motors without differential gear. For traction unit, prototype IPMSM and inverter have been developed. The IPMSM was designed by CAD program that was developed with both equivalent circuit method and FEM. Also the inverter was developed to drive 2 motors with 6 legs IGBT switches in a control board. The vector control algorithm was implemented with maximum torque control method in the constant torque region and field weakening control method in the constant power region considering inverter capacity. To verify that the traction unit is more high efficiency and has more high power density than a traction unit with induction motor with the same power, we would like to show the results about the design and analysis of the IPMSM and the experiment results about the traction unit.

• 한국철도학회논문집
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• 제15권2호
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• pp.129-134
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• 2012

NPC 멀티레벨 인버터는 2-레벨 인버터 방식에 비해 전력용 반도체 소자의 정격 전압과 출력전류의 고조파를 감소시킬 수 있는 장점이 있어 고압 대용량 전동기 구동시스템에 적합하다. NPC 3-레벨 인버터를 이용한 IPMSM의 속도 제어에서 일정 토크 영역에서는 최대 토크 제어, 일정 출력 영역에서는 약계자 제어 방식을 적용하였다. 제안된 시스템은 MATLAB/Simulink를 이용한 시뮬레이터를 구현하여 모의 시험 결과 분석을 통해 그 타당성을 검증하였다.

• 한국항공우주학회지
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• 제35권3호
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• pp.231-237
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• 2007

EHA용 유압 펌프의 토크 맥동은 저속 회전 영역에서 실린더 위치의 제어에 외란으로 작용할 수 있다. 원칙적으로 피스톤 펌프에 의해 발생되는 반력 토크의 주기적인 변화는 실린더 압력의 파형과 밀접한 관계를 가지고 있다. 일정 속도로 회전하는 단방향 피스톤 펌프의 경우에는 밸브 플레이트의 예압각이나 노치를 활용하여 실린더 압력의 오버슈트나 변화율을 조절할 수 있다. 따라서 본 연구에서는 밸브 플레이트의 형상이 EHA용 사축식 유압 피스톤 펌프의 토크 맥동에 미치는 영향을 분석하였다. 그 결과로서, 양방향 회전형 유압 피스톤 펌프의 토크 맥동은 회전 속도의 영역에 무관하게 밸브 플레이트의 예압각이나 노치를 이용하여 개선하는 것이 불가능한 것으로 나타났다.