• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2001년도 전력전자학술대회 논문집
• /
• pp.487-490
• /
• 2001

Power Quality and Reliability are becoming important issues for critical and sensitive loads. This paper describes the Line Interactive UPS with the function of Voltage Compensator that is 'Line interactive Dynamic Voltage Restorer(LIDVR). The main purpose of a LIDVR is to compensate for voltage sag(dip), outage and overvoltage. The overall system consists of three controller 1) current controller with prediction 2) voltage controller and 3) proposed variable DC LINK controller. The variable DC LINK control technique using the LIDVR protects DC LINK from overflowing the input current. The simulation results are depicted in this paper to show the effect of this proposed system.

• 한국정밀공학회지
• /
• 제25권6호
• /
• pp.62-70
• /
• 2008

An adaptive fuzzy backstepping controller is proposed for the motion control for a single-link flexible-joint robot in the presence of parametric uncertainties. Fuzzy logic system is used to approximate the uncertainties of functions and a backstepping technique is employed to deal with the mismatched problem. A compensation controller is also employed to estimates the bound of approximation error so that the shattering effect of the control effort can be reduced. Thus the asymptotic stability of the closed loop control system can be obtained based on a Lyapunov synthesis approach. Numerical simulation results for a single-link flexible-joint robot are included to show the effectiveness of proposed controller.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 B
• /
• pp.1161-1165
• /
• 2004

The fundamental digital control of utility-connected PV inverter are presented with detailed analysis and simulation and experimental results. PLL controller using virtual two phase detector, current controller of DC-DC converter, dc link voltage controller and inverter current controller are discussed. The novel PLL controller using virtual two phase detector can detect the information of utility voltage instantaneously and is not sensitive to the noise. Current controller of DC-DC converter, dc link voltage controller and inverter current controller are the conventional methods. We have constructed utility-Connected PV Inverter and applied to those controllers. The simulation and experimental results demonstrate an excellent performance in the single-phase grid-connected operation.

• 한국정보과학회:학술대회논문집
• /
• 한국정보과학회 2000년도 봄 학술발표논문집 Vol.27 No.1 (A)
• /
• pp.45-47
• /
• 2000

본 연구는 심볼릭 모델 체커 중의 하나인 SMV(Symbolic Model Verifier)를 이용하여 한국전자통신연구원(ETRI)에서 개발한 CCA(Cache Coherent Agent) 보드를 위한 I-Link Bus(Inside Bus)의 몇 가지 특성(property)들을 검증하여 I-Link Bus의 요구사항(requirement)이 만족됨을 보인다. 이 검증에서는 I-Link Bus의 모델을 SMV 입력 언어로 명세하며, 검증할 특성들을 시제 논리(temporal logic)를 이용하여 나타낸다. 검증을 통해서 I-Link Bus와 PIF(Processor Interface), DC(Directory Controller), RC(Remote access cache Controller)모듈들이 중재기 우선 순위, send 우선 순위, 중재 요청 신호의 관리, liveness등의 특성들을 만족한다라는 것을 검증하였다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
• /
• pp.734-738
• /
• 1996

An adaptive output feedback controller is designed for tracking control of an n-link robot manipulator with unknown load. High-gain observers with same structure as error dynamic systems are used to estimate joint velocities. The parameter adaptation is achieved by the smoothed projection algorithm. The control inputs are saturated outside a domain of interest. Simulation results on a 2-link manipulator illustrate that when the speed of the high-gain observer is sufficiently high, the proposed controller recovers the performance under state feedback control.

• Journal of Electrical Engineering and Technology
• /
• 제8권5호
• /
• pp.1122-1130
• /
• 2013

This paper proposes a new design for quick battery charger systems for electric vehicles that consists of a three-phase inverter and a full-bridge converter which use the phase-shift method. The 3-phase inverter controls the input and DC-link voltage by use of a current controller and a voltage controller. The full-bridge converter transfers the DC-link voltage to a fixed output voltage. Designs for the output-side converter and controller for improved performance are proposed in this paper. Design schemes for the filter and controller of an input-side inverter are also presented. Furthermore, the paper proposes a compensation method for the offset current that is caused by switch failure and circuit problems. Simulations and experiments have been performed on a 50kW-battery charger system that is suitable for vehicles. The presented results verify the validity of the proposed method and the superiority of the system over conventional methods.

• Journal of Power Electronics
• /
• 제16권5호
• /
• pp.1928-1938
• /
• 2016

The three-phase four-wire shunt active power filter (APF) is an effective method to solve the harmonic problem in three-phase four-wire power systems. In addition, it has two possible topologies, a four-leg inverter and a three-leg inverter with a split-capacitor. There are some studies investigating DC-link voltage control in three-phase four-wire APFs. However, when compared to the four-leg inverter topology, maintaining the balance between the DC-link upper and lower capacitor voltages becomes a unique problem in the three-leg inverter with a split-capacitor topology, and previous studies seldom pay attention to this fact. In this paper, the influence of the balance between the two DC-link voltages on the compensation performance, and the influence of the voltage balance controller on the compensation performance, are analyzed. To achieve the balance between the two DC-link capacitor voltages, and to avoid the adverse effect the voltage balance controller has on the APF compensation performance, a new DC-link voltage balance control strategy for the three-phase four-wire split-capacitor APF is proposed. Representative simulation and experimental results are presented to verify the analysis and the proposed DC-link voltage balance control strategy.

• Transactions on Control, Automation and Systems Engineering
• /
• 제2권4호
• /
• pp.221-227
• /
• 2000

This paper combines the constrained model predictive control with the feedback linearization to solve a nonlinear system control problem with input constraints. The combined approach consists of two steps: Firstly, the nonlinear model is linearized by the feedback linearization. Secondly, based on the linearized model, the constrained model predictive controller is designed taking input constraints into consideration. The proposed controller is applied to two link robot system, and tracking performances of the controller are investigated via some simulations, where the comparisons are done for the cases of unconstrained, constrained input in feedback linearization.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 D
• /
• pp.2467-2469
• /
• 2001

A strategy for the swing-up and stabilization control method for a two-links rotational pendulum according to states of each link of the rotational pendulum is proposed. The proposed controller consists of two modes of control such as divergence mode and stabilization mode. When the controller is in divergence mode, control input is generated using sinusoidal function, which is developed based on resonance period of the pendulum in linear region, to make the second link (pendulum) reach top position. After the controller finishes operation in divergence mode, stabilization control is initiated to keep the pendulum around the top position using pole placement control method. Experimental results are given to show the effectiveness of the proposed method.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
• /
• pp.8-13
• /
• 1998

A tracking controller is presented for RLFJ(rigid link flexible joint) robot manipulators with only position measurements. The controller is developed based on the integrator backstepping design method and on the two observers: the first is simple linear form observer for the filtered link velocity errors and the other for the actuator velocities. The proposed controller achieves exponential tracking of link positions and velocities while keeping all internal signals bounded. It also guarantees exponential convergence of the estimated signals to their actual ones. Finally, simulation results are included to demonstrate the tracking performance.