• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.672-674
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• 2004

Many nonlinear controllers for the power system are based on nonlinear models involving the power angle as an element of the state, and therefore the reference value for the power angle is needed. As this reference value is not generally available, it is difficult to apply such nonlinear control methods in practice. To deal with this problem, we present an input-output feedback linearizing control scheme by selecting the output as a combination of the squared voltage and the relative frequency. It is shown that the internal dynamics are locally stable with controllable damping, and that the frequency remains bounded for all time. Simulations illustrate the effectiveness of the proposed method.

• 한국전자파학회논문지
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• 제14권2호
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• pp.183-191
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• 2003

본 논문은 동일 주파수 무선통신 시스템에서 발생되는 궤환신호를 상쇄하기 위한 간섭잡음제거기에 관한 연구이다. 송신 안테나에서 수신 안테나로 시변 궤환되는 신호는 수신 시스템의 성능을 저하시킨다. 따라서, 본 논문에서는 이러한 시변 궤환신호를 제거하므로써 수신기의 발진현상을 방지하고 전력증폭기의 최대 출력을 지속적으로 유지하도록 하는 적응성 궤환방식을 이용한 간섭잡음제거기를 제안하였다.

• IEIE Transactions on Smart Processing and Computing
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• 제2권3호
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• pp.160-167
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• 2013

Resource allocation based on quantized feedback plays a critical role in wireless mesh networks with a time division multiple access (TDMA) physical layer. In this study, a resource allocation problem was formulated based on quantized feedback for TDMA wireless mesh networks that minimize the total transmission power. Three steps were taken to solve the optimization problem. In the first step, the codebook of the power, rate and equivalent channel quantization threshold was designed. In the second step, the timeslot allocation criterion was deduced using the primal-dual method. In the third step, a resource allocation scheme was developed based on quantized feedback using the stochastic optimization tool. The simulation results show that the proposed scheme not only reduces the total transmission power, but also has the advantage of quantized feedback.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.87-90
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• 2003

In this paper, A feedforward linear power amplifier is analyzed for imperfect signal cancellation and negative feedback for basestaion of IMT2000 band. the distortion generatied by the error amplifier is reduced using an imperfect signal cancellation for a 1-carrier WCDMA source by 4.3dB at 2.5MHz offset and 6dB at 5MHz offset of IMSR(intermodulation signal power ratio) compared to a perfect signal cancellation system. additionally, An imperfect signal cancellation using negative feedback improved 1.3dB and 8.2dB at 2.5MHz and 5MHz offset of IMSR compared to an imperfect signal cancellation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2672-2674
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• 2000

In this paper. feedback linearization and the sliding mode control(SMC) are used together for uncertain nonlinear system. An advantage of feedback linearization technique is to make linear control theories can be used for nonlinear system and the SMC have the robustness. But the dynamics of the SMC has the dynamics lower order than that of the original system. Therefore the linear control theory can not be used with the SMC. The novel sliding surface of the SMC can have the dynamics of the nominal non linear system controlled by the feedback linearization. The proposed method can be used for the control of induction motors.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.438-443
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• 1998

A simple single-stage AC/DC forward converter with transformer magnetic energy feedback technique for power factor correction is proposed. The operational principle of the proposed converter is presented. The proposed converter gives the good power factor correction, low line current harmonic distortions, and tight output voltage regulation. The prototype shows high power factor with low line current harmonics.

• 제어로봇시스템학회논문지
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• 제21권12호
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• pp.1152-1159
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• 2015

Switching power supply systems are widely used in many industrial fields. Power factor correction (PFC) circuits have a tendency to be applied in new power supply designs. The PFC circuit with a boost converter using an input power source is studied in this paper. In a boost PFC circuit, there are two feedback control loops: a current feedback loop and a voltage feedback loop. In this paper, the regulation performance gained by using the output voltage and compensator to improve the transient response presented at the continuous conduction mode (CCM) of the boost PFC circuit is analyzed. The validity of the designed boost PFC circuit is confirmed by both MATLAB simulation and experimental results.

• 제어로봇시스템학회논문지
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• 제9권12호
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• pp.1065-1070
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• 2003

We present a power control with variable state feedback gain (VFPC) to improve outage convergence rate of distributed constrained power control. The variable state feedback gain includes the information of the desired SIR changes and must be a decreasing sequence for the convergence. The proof of the convergence is given. The proposed algorithm can improve the outage convergence rate and SIR (Signal to Interference Ratio) response at transient as well as at steady state. The simulation results are given to demonstrate the feasibility of the proposed scheme.

• 제어로봇시스템학회논문지
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• 제13권1호
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• pp.1-5
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• 2007

Many nonlinear controllers for the power system are based on nonlinear models involving the power angle as an element of the state, and therefore the reference value for the power angle is needed. As this reference value is not generally available, it is difficult to apply such nonlinear control methods in practice. To deal with this problem, we present an input-output feedback linearizing control scheme by selecting the output as a combination of the squared voltage and the relative frequency. It is shown that the internal dynamics are locally stable with controllable damping, and that the frequency remains bounded for all time. Simulations illustrate the effectiveness of the proposed method.

• Journal of Power Electronics
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• 제16권2호
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• pp.621-630
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• 2016

In this paper, a single current sensor technique (SCST) is proposed for single-phase full-bridge inverters. The proposed SCST measures the currents of multiple branches at the same time, and reconstructs the average inductor, capacitor, and load current in a single switching cycle. Since all of the branches' current in the LC filter and the load are obtained using the SCST, both the inductor and the capacitor current feedback schemes can be selectively applied while taking advantages of each other. This paper also analyzes both of the current feedback schemes from the view point of the closed-loop output impedance. The proposed SCST and the analysis in this paper are verified through experiments on a 3kVA single-phase uninterruptible power supply (UPS).