• Proceedings of the IEEK Conference
• /
• 2001.06a
• /
• pp.117-120
• /
• 2001

In this paper, we propose a robust trellis coded modulation for a correlated Rayleigh fading channel. This method use only one transmit antenna, which can achieve superior performance compared to Space-Time Trellis Coded Modulation (STTC) over a wide channel correlation range among transmit antennas. The code is designed to have the largest Euclidean distance between faded signals at the receiver. Computer simulations are performed to evaluate the frame error rate (FER) performance and to compare the proposed code with the conventional one.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.259-259
• /
• 2000

In the recent, the size of hardware is smaller and the structure is simpler, without reducing the performance of the digital controller. Accordingly, the fixed-point arithmetic is very important in the digital controller. This paper presents simulation to apply the robust control algorithms to DVDR servo controller using the floating-point and fixed-point arithmetic from the matlab. Also, it analyses and compares the performance of control algorithms in the each of point calculation and presents a method for improvement of drop in the performance, quantization error and overflow/underflow from using the fixed-point arithmetic

• Nuclear Engineering and Technology
• /
• v.32 no.2
• /
• pp.157-168
• /
• 2000

The nuclear steam generator level control system is designed by robust control methods. The feedwater controller is designed by three methods of the H$\infty$, the mixed weight sensitivity and the structured singular value. Then the controller located on the feedback loop of the level control system is designed. For the system performance, the controller of simple PID whose coefficients vary with the power is selected. The simulations show that the system has a good performance with proper stability margins.

• 제어로봇시스템학회:학술대회논문집
• /
• 1998.10a
• /
• pp.157-160
• /
• 1998

We argue that the combination of optimal control synthesis and QFT tuning enables design of controllers with levels of performance that surpasses what can be achieved using only a single technique. Using a constructive example, we demonstrate how the strength of each technique is utilized to arrive at a particularly desired controller in terms of tradeoffs between performance and controller complexity.

• Journal of Power Electronics
• /
• v.15 no.3
• /
• pp.695-701
• /
• 2015

Uninterruptible Power Supplies (UPSs) can be largely divided into the passive-standby, line-interactive and double-conversion methods. This paper proposes a double-conversion UPS with a low cost and high performance. This single phase UPS uses a single-loop robust voltage controller and 1-switch voltage doubler strategy PFC. The proposed UPS is composed of a single phase PFC, a half-bridge inverter, a battery charger and a battery discharger. Finally, the validity of proposed UPS was verified by various experimental tests.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.903-908
• /
• 2003

In this paper, we present an observer-based robust controller which achieves not only robust stability but also an performance robustness for linear uncertain discrete-time systems. The performance robustness means that comparing the transient behavior of the uncertain system with a desired one generated by the nominal system, the deterioration of control performance (i.e. the error between the real response and the desired one) is suppressed without excessive control input. The control law consists of a state feedback law for the nominal system and a compensation input given by a feedback form of an estimated error signal. In this paper, we show that conditions for the existence of the observer-based controller are given in terms of linear matrix inequalities (LMIs). Finally, a numerical example is given to illustrate the proposed technique.

• Proceedings of the KIPE Conference
• /
• 2001.10a
• /
• pp.374-379
• /
• 2001

In this paper, a novel design algorithm of speed controller for an Induction motor with the inertia variation is proposed. The main contribution of our work is a very robust, reliable and stable procedure for setting of the PI gains against the specified range of the inertia variation of an induction motor using Kharitonovs robust control theory. Therefore, the basic segment of controller design, the variation of induction motor inertia is estimated by the RLS (Recursive least square) method. PI based speed controller is widely used in industrial application for its simple structure and reliable performance. In addition the Kharitonov robust control theory is used for verification stability of closed-loop transfer function. The performance of this proposed design method is proved by digital simulation and experimentation with high performance DSP based induction motor driving system.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10b
• /
• pp.355-359
• /
• 1993

This paper deals with the problem of robust TDF(Two Degree of Freedom) H$_{\infty}$ control design for a linear system with parameter uncertainty in the state space model. The uncertain system considered here is with the time-invariant norm-bounded parameter uncertainty in the state matrix. A TDF H$_{\infty}$ control design is presented which robustly stabilizes the plant, guarantees the robust H$_{\infty}$ performance and improves the tracking performance for the closed-loop system in the face of parameter uncertainty. It is shwon that a suitable stabilizing control law can be constructed in terms of a positive definite solution to a certain parameter-dependent algebraic Riccati equation and a good tracking performance can be constructed in terms of suitable feedforward control law.aw.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10b
• /
• pp.105-108
• /
• 1993

This paper is concerned with a two-degree-offreedom control system design for a flexible arm, a two-degree-of-frecdom control system can achieve a robust stability specification and a control performance specification independently. By this property we improve the control performance with maintaining the same robust stability level as that of the onc-dcgree-of-freedom control system. At First we design a two-degree-of-fteedom control system which includes a feedforward controller and a feedback controller. The feedforward controller can be given by specifying a transfer function of a dcsired closed-loop model. We obtain a feedback controller by solving a mixed sensitivity problem. Several numerical results show that two-degree-of-freedom control systems acheive a better control performance than that of one-degree-of-freedom control systems.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10b
• /
• pp.95-99
• /
• 1993

In this paper, we discuss H$_{\infty}$ robust performance problem for uncertain system described in a descriptor form. We show that the method based on Riccati equation can be extended to solve this problem. First, such a sufficient condition is given that the system described in a descriptor form is quadratic stable and H$_{\infty}$ norm of a specified transfer function is less than a given level. Using this result, a state feedback law which ensures H$_{\infty}$ robust performance of closed loop system is derived based on a positive definite solution of a Riccati equation. This result shows that a solution of the problem can be also obtained by solving H$_{\infty}$ standard problem for an extended plant. Finally, a design example and simulation results will be given.ven.