• Journal of Power Electronics
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• 제4권2호
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• pp.96-101
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• 2004

This paper presents an application of SRM drive for LSEV(Low Speed Electric Vehicle). In this paper, a 5〔㎾〕 SRM for a traction of a LSEV is to design and investigate the characteristics of the drive system. The main design parameters and control strategy are given. In the control method, a current control, for the soft-starting technique at a starting operation, is adopted. In the high speed range, an angle control technique is implemented, for a high efficiency drive of SRM. Some experimental tests are executed to find the drive performances.

• Journal of Power Electronics
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• 제19권5호
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• pp.1193-1202
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• 2019

A SMPMSM drive system is a typical nonlinear system with time-varying parameters and unmodeled dynamics. The speed outer loop and current inner loop control structures are coupled and coexist with various disturbances, which makes the speed control of SMPMSM drive systems challenging. First, an ultra-local model of a PMSM driving system is established online based on the algebraic estimation method of model-free control. Second, based on the backstepping control framework, model-free adaptive integral backstepping (MF-AIB) control is proposed. This scheme is applied to the permanent magnet synchronous motor (PMSM) drive system of an electric vehicle for the first time. The validity of the proposed control scheme is verified by system simulations and experimental results obtained from a SMPMSM drive system bench test.

• 한국자동차공학회논문집
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• 제19권1호
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• pp.17-24
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• 2011

TMED(Transmission Mounted Electric Device) parallel hybrid configuration can realize EV(Electric Vehicle) mode by disengaging the clutch between an engine and a transmission-mounted motor to improve efficiencies of low load driving and regenerative braking. In the EV mode, however, jerk can be induced since there are insufficient damping elements in the drive-train. Though the jerk gives demoralizing influence upon driving comport, adding a physical damper is not applicable due to constraints of the layout. This study suggests the jerk reduction control, composed of active damping method and torque profiling method, to suppress the jerk without hardware modification. The former method creates a virtual damper by generating absorbing torque in the opposite direction of the oscillation. The latter method reduces impulse on the mated gear teeth of the drive-train by limiting the gradient of traction torque when the direction of the torque is reversed. To validate the effectiveness of the suggested strategy, a series of vehicle tests are carried out and it is observed that the amplitude of the oscillation can be reduced by up to 83%.

• 전력전자학회논문지
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• 제5권1호
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• pp.95-103
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• 2000

본 논문에서는 브러시리스 직류 전동기용 센서리스 드라이브의 성능 향상을 위한 새로운 회전자 위치 간접 검출 방식을 제안한다. 단자 전압을 이용하는 기존의 회전자 위치 간접 검출 방식들은 전동기를 동기 모드로 운전시 과도한 전압이 인가되면 회전자 위치를 정확히 검출할 수 없기 때문에 센서리스 운전 모드로의 신속한 전환이 어렵다. 따라서 본 논문에서는 전동기를 동기 모드로 운전하는 경우, 과전압에 의한 단자 전압과 역기전력 파형의 관계를 분석하여 저속 운전 영역에서도 회전자 위치를 정확히 검출할 수 있는 새로운 간접 검출 방식을 제안한다. 또한 실험을 통하여 제안한 방식의 효용성을 입증한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.270-272
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• 2005

In this paper, we proposed a new method detecting actions of some components driven by the coil excitation. Nuclear power reactors are typically controlled by the movement of several neutron-absorbing control rods into or out of the reactor core. For moving control rods, we use an electromagnetic-jack-typed mechanism, which is called Control Rod Drive Mechanism. This mechanism moves control rods by the step composed of sequential actions of components. In case any mechanical problems happen in the mechanism, the orders for the control rod movement from the higher system cannot be performed properly. This abnormal state must be monitored and the sequential actions of the components can be the monitoring target. The actions of components generate some deviations in the profiles of the currents flowing into the coils in the mechanism. We focused on this phenomena and devised a new method of detecting the actions of the components in Control Rod Drive Mechanism by using the wavelet transform for observing the current profile.

• 전기학회논문지
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• 제56권11호
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• pp.2004-2009
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• 2007

A new high-speed drive method for the plasma display panel is proposed. In this method, the address period is inserted for the rest period of the sustain pulses and the priming pulse is applied on the entire panel at the same time overlapping with the sustain period. The ramp shaped priming pulse can be made with a simple drive circuit in this technology and the stable sustain discharge can be induced even by a narrow scan pulse in help of the space charge generated from the address discharge. From the experiments, it is ascertained that the priming pulse hardly influences the sustain discharge. Moreover, the voltage margin of the sustain discharge is almost constant though that of the address discharge broadens with narrowing the scan pulse width. And, if the time interval between the scan pulse and the sustain pulse is within $6{\mu}s$, the voltage margin of the address and the sustain discharges are unaffected though the applied position of the scan pulse is changed. High-speed driving with the address pulse of $0.7{\mu}s$ width was achieved and the address voltage margin of 20V and the sustain voltage margin of 10V were obtained.

• 한국전자통신학회논문지
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• 제16권1호
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• pp.109-116
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• 2021

RDF(Resource Description Framework) 데이터 구조는 그래프로 모델링하기 때문에, 관계형 데이터베이스와 XML 기술의 기존 솔루션은 RDF 모델에 바로 적용하기 어렵다. 우리는 링크 데이터를 더욱 효과적으로 저장하고, 인덱스하고, 검색하기 위해 융합 인덱싱 방법을 제안한다. 이 방법은 HDD(Hard Disk Drive) 와 SSD(Solid State Drive) 디바이스에 기반한 하이브리드 스토리지 시스템을 사용하고, 불필요한 데이터를 필터하고 중간 결과를 정제하기 위해 분리된 필터 및 정제 인덱스 구조를 사용한다. 우리는 3개의 표준 조인 검색알고리즘에 대한 성능 비교를 수행했는데, 실험 결과 제안된 방법이 Quad와 Darq와 같은 다른 기존 방법들에 비해 뛰어난 성능을 보인다.

• 동력기계공학회지
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• 제12권2호
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• pp.41-47
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• 2008

This article deals with the stress analysis of the friction drive, which transmits the power via the rolling resistance on the contract area between the two rotating bodies. On the contact area, friction drives are normally involved with shear stress due to the transmitted force, as well as normal stress. Thus the stress analysis including the shear stress is necessary for the design of the friction drive. Hertzian results can be used to estimate the normal stress distribution and elastic deflection of the contact area, although the shear stress distribution is not well defined. In order to investigate the shear stress distribution and its effects in a friction drive, we have performed the stress analysis of the spherical continuously variable transmission(CVT) using finite element method. The spherical CVT is one of friction drives, which is used in small power applications. The numerical results show that the normal stress distribution is not affected by the transmitted shear force, and the maximal shear stress is increased in small amount along with the shear force.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.570-575
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• 2002

Servo performance of a disk drive is greatly affected by the mechanical resonance frequencies of the head gimbal assembly (HSA). It is important factor to allow broader bandwidths for servo system in improving overall drive performance. In this paper, an optimal design for ODD suspension is attempted to increase resonance frequencies in tracking direction. Initial model was designed and the design parameter was defined to the model. The mode frequency variation for the change of design parameter was observed by modal analysis using the finite element method(FEM). The sensitivity matrix was calculated from the observed data and so through sensitivity analysis, an optimized ODD suspension was designed to have the higher resonant frequency than the initial model.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.1014-1017
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• 1988

Direct-drive robots have excellent features including no backlash, small friction, and high mechanical stiffness. However, dynamic coupling among joints as well as nonlinear effects become more prominent than traditional robots with reducers. Another critical issue is that the robot becomes more sensitive to the change of load. In this paper, we develop a simple current feedback scheme for reducing the influence of dynamic coupling and load sensitivity on the direct-drive robots. The method is implemented on a 2 d.o.f. planar direct-drive robot. Then the validity of the method is demonstrated through experiments.