• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.570-572
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• 2003

체감 효과 (haptic effect)는 가상 환경에서의 실재감 부여를 위하여 중요시되고 있다. 반면, 가상 객체에 실재와 흡사하게 연동하는 기술은, 체감 효과의 모델링과 함께 렌더링 시간 둥의 문제 때문에 사용의 한계를 가진다. 본 논문에서는, 실시간 체감 효과를 위하여 필수적인 가상 객체와의 동기화 기법에 대하여 다룬다. 이를 위하여, 가상 객체에 작용하는 동역학적 움직임을 체감 효과에 대응되도록 하는 알고리즘을 제안하고, 이를 실시간 충들 처리와 연동함으로써 필요한 시간을 최소화 할 수 있음을 제시한다. 본 논문의 결과로는 캐릭터의 빈번한 제어에 대응되도록 체감 효과를 생성할 수 있음을 보이며, 안정적이면서 그럴 듯한 효과를 재현할 수 있음을 보인다.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.2
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• pp.159-163
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• 2006

In order to tune the speed controller in the linear servo applications an accurate information of a mover mass including a load mass is always required. This paper suggests the mass estimation method of a permanent magnet linear synchronous motor(PMLSM) 4y using the parameter estimation method of Least-Squares algorithm. First, the deterministic autoregressive moving average(DARMA) model of the mechanical dynamic system is derived. Then the application of the Least-Squares algorithm shows that the mass can be accurately estimated both in the simulation results and in the experimental results.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.166-169
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• 2005

대용량 동기 발전 전동기 운전의 기동용 시스템으로 주로 사이리스터를 이용한 정지형 주파수 변환(SFC : Static Frequency Converter) 시스템이 사용되고 있다. 본 논문에서는 SFC시스템의 기동부터 회생까지 파형을 5KVA급 동기 전용 발전기 모의실험을 통하여 제시하고 330MVA급 양수 발전소의 실측 파형을 분석하여 알고리즘을 도출하였으며 또한 시뮬레이터 파형과 실제 파형을 비교해 함으로써 양수발전소의 제어 시스템의 운전특성을 유추 및 분석하였다.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.22-24
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• 2008

영구자석 동기전동기(Permanent Magnet Synchronous Motor)를 벡터 제어로 구동 시 정확한 회전자 위치정보가 요구된다. 일반적으로 레졸버(Resolver)를 이용하면 회전자의 절대 위치(absolute position)를 알 수 있다. 하지만 레졸버의 변압비 차이, 불평형 여자신호, 불균일한 인덕턴스 성분, 신호처리 회로상의 왜곡으로 인해 신호의 크기 불평형이 발생하고 이는 위치정보에 주기적인 오차 성분이 나타나게 되며, 이러한 오차 성분들은 토크에 영향을 준다. 본 논문에서는 이러한 오차 성분을 수학적 해석을 바탕으로 확인하고 보상하는 방법을 제안하였다. 제안된 알고리즘의 타당성을 실험을 통해 검증하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.9
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• pp.469-478
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• 2001

It is difficult to test a distributed system because of the task of controlling concurrent events,. Existing works do not propose the test sequence generation algorithm in a formal way and the amount of message is large due to synchronization. In this paper, we propose a formal test sequence generation algorithm using logical clock to control concurrent events. It can solve the control-observation problem and makes the test results reproducible. It also provides a generic solution such that the algorithm can be used for any possible communication paradigm. In distributed test, the number of channels among the testers increases non-linearly with the number of distributed objects. We propose a new remote test architecture for solving this problem. SDL Tool is used to verify the correctness of the proposed algorithm and it is applied to the message exchange for the establishment of Q.2971 point-to-multipoint call/connection as a case study.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.5
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• pp.329-335
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• 2008

Recently, super high-speed motor drives have been available due to the development of power electronics technology And they are used in various fields of industry because of their advantages. This paper describes the control algorithm for a permanent magnet synchronous motor(PMSM) drive at the speed of 118,000r/min using DSP and IGBT inverter. Hall sensors are implemented to measure the rotor position and speed, and a speed observer is used to reduce the performance deterioration caused by the low resolution of hall sensors. To enhance the output power capacity in the high-speed operating region, a flux weakening controller which also can work as an anti-wind up controller is used. Computer simulations and experiments are peformed to validate the proposed method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.175-181
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• 2009

In this paper, it is suggested that the selection method of parameter of Power System Stabilizer(PSS) with robustness in low frequency oscillation for Static VAR Compensator(SVC) using a self tuning fuzzy controller for a synchronous generator excitation and SVC system. The proposed parameter self tuning algorithm of fuzzy controller is based on the steepest decent method using two direction vectors which make error between inference values of fuzzy controller and output values of the specially selected PSS reduce steepestly. Using input-output data pair obtained from PSS, the parameters in antecedent part and in consequent part of fuzzy inference rules are learned and tuned automatically using the proposed steepest decent method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.6
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• pp.40-50
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• 2002

In this paper, we present a GA(Genetic Algorithm) approach to select weighting matrices of an optimal LQ(Linear Quadratic) controller for SVC(Static VAR Compensator). A SVC, one of the FACTS(Flexible AC Transmission System), constructed by a FC(Fixed Capacitor) and a TCR(Thyristor Controlled Reactor), was designed and implemented to improve the damping of a synchronous generator, as well as to control the system voltage Also, a design of LQ controller depends on choosing weighting matrices. The selection of weighting matrices which is not a trivial solution is usually carried out by trial and error. We proposed an efficient method using GA of finding weighting matrices for optimal control law. Thus, we proved the usefulness of proposed method to improve the stability of single machine-infinite bus with SVC system by eigenvalues analysis and simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.3
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• pp.275-284
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• 1999

Unbalanced source voltage in the 3-phase power system is decomposed into positive, negative and zero sequence c components. Also, assuming there is no neutral path in the system, the zero sequence component is not shown on the l load side. Therefore, in the unbalanced power system without neutral path. it is possible to provide balanced voltage to t the load side by compensating negative sequence component and also to regulate the voltage amplitude by controlling t the positive sequence component. In addition, the symmetrical components due to voltage unbalance can be effectively d detected on the synchronous reference frame by using dlongleftarrowq transformation. In this paper, an algorithm not only c compensating unbalanced source voltage by canceling the negative sequence component on the synchronous reference f frame but also maintaining load voltages constantly is proposed. Also a novel method for phase angle detection s synchronized by positive sequence component under unbalanced source voltage is suggested and this detected phase a angle is used for d-q transformation. The performances and characteristics of the proposed compensating system are a analyzed by simulation and verified through experimental results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.26-33
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• 2016

Recently, the use of transformer-less UPS has increased to improve the efficiency of UPS. However, transformer-less UPS is required in three-phase four-wire input IGBT PWM rectifier and the existing three-phase three-wire PFC algorithm cannot be applied in the three-phase four-wire system due to the neutral current problem of UPS input. To control the three-phase four-wire input IGBT PWM rectifier, there are two existing algorithms: 3D SVM and single phase control method. These two algorithms have advantages/disadvantages in controlling the rectifier. The single phase control method is unstable for controlling the rectifier and the 3D SVM method has a problem that must increase the L value of the input-side inductor considerably. Therefore, this paper proposes digital single phase control technology and another new algorithm considering the d-q control, to improve the characteristics of the existing control algorithm. In addition, this paper performed a simulation and experiment based on the proposed control algorithm. The simulation results showed that the proposed technology can control three-phase four-wire IGBT PWM rectifier in a stable manner and can also reduce the neutral current. The proposed algorithm is a useful tool for controlling the three-phase four-wire IGBT PWM rectifier.