• Title/Summary/Keyword: feedforward loop control

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Design and Fabrication of 10W Feedforward Linear Power Amplifier adding Feedback Loop for IMT-2000 (궤한루프를 첨가한 IMT-2000용 10W급 Feedforward 선형 전력 증폭기의 설계 및 제작)

  • 류병하;장중호;김성민;최현철
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2000.11a
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    • pp.187-190
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    • 2000
  • In this paper, A Feedforward Linear Power Amplifier which is appended a feedback loop for IMT-2000 was designed and fabricated. Feedback loop was used to improve the IMD(Inter-Modulation Distortion) characteristics of the main amplifier. And it is easy to cancel IMD on the min path and control IMD cancellation loop, compared with basic Feedforward Linear Power Amplifier. This feedback loop has the same effect of the Predistroter. So, This power amplifier was improved in IMD characteristics to add the effect of Predistroter to basic Feedforward amplifier. And the disigned power amplifier in this paper represented the 40dBm(10W) output and -55dBc 3rd IMD at center frequency 2.14GHz (@10MHz).

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Volume Velocity Control of Active Panel to Reduce Interior Noise (실내소음 저감을 위한 능동패널의 체속도 제어)

  • 김인수
    • Journal of KSNVE
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    • v.9 no.1
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    • pp.33-41
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    • 1999
  • This paper presents a method of actively controlling the interior noise by a trim panel with hybrid feedforward-feedback control loop. The control technique is designed to minimize the vibration of panel whose motion is limited to that of a piston (out-of-plane motion). The hybrid controller consists of an adaptive feedforward controller in conjunction with a linear quadratic Gaussian (LQG) feedback controller. In order to maintain control performance of both persistent and transient disturbances, the feedback loop speeds up the adaptation rate of feedforward controller by improving damping capacity of secondary plant related with the adaptation rule. Numerical simulation and experimental result indicate that the hybrid controller is a more effective method for reducing the vibration of the panel (and therefore the interior noise) compared to using feedforward controller.

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The Design of the Amplitude and Phase Control Circuit for the Error Sensor Loop in Feedforward Linearizer System (Feedforward 선형화기 시스템의 오차 추출 루프를 위한 크기와 위상 제어 회로의 설계)

  • Nam, Sang-Dae;Park, Ung-Hui;Jang, Ik-Su;Yun, Sang-Won
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.37 no.2
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    • pp.91-97
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    • 2000
  • Tn this paper, a novel control circuit applicable to the error sensor loop block in the feedforward linearizer system is proposed. The proposed control circuit is applied to the error sensor loop block, where in the 11dB power range, it operates stably, and makes main carrier signals to be eliminated more than 40dB below 3$\^$rd/ order IM level. In the operating point, the amplitude control error is 0.05∼0.12dB, and the phase control error is smaller than 0.02。. It is verified theoretically as well as experimentally that the control circuit can precisely compensate the variation of nonlinear characteristics in a high power amplifier, due to the variations of input power, operating temperature, humidity and the other system environments.

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Precise Position Control of Piezoelectric Actuators without Nonlinear Hysteresis Model (비선형 히스테레시스 모델을 채용하지 않는 압전구동기의 정밀위치제어)

  • 송재욱;송하성;김호상
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.189-193
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    • 1996
  • Piezoelectric actuator is widely used in precision positioning applications due to its excellent positioning resolution. However, serious hysteresis nonlinearity of the actuator deteriorates its open loop positioning capability. Generally, a nonlinear hysteresis model is used in feedforward loop to improve positioning accuracy. In this study, however, a simple lead compensator is proposed as a substitution for a complex nonlinear hysteresis model and tested through experiments for precision position control.

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Precision Position Control of Piezoelectric Actuator Using Feedforward Hysteresis Compensation and Neural Network (히스테리시스 앞먹임과 신경회로망을 이용한 압전 구동기의 정밀 위치제어)

  • Kim HyoungSeog;Lee Soo Hee;Ahn KyungKwan;Lee ByungRyong
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.7 s.172
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    • pp.94-101
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    • 2005
  • This work proposes a new method for describing the hysteresis non-linearity of a piezoelectric actuator. The hysteresis behaviour of piezoelectric actuators, including the minor loop trajectory, are modeled by geometrical relationship between a reference major loop and its minor loops. This hysteresis model is transformed into inverse hysteresis model in order to output compensated voltage with regard to the given input displacement. A feedforward neural network, which is trained by a feedback PID control module, is incorporated to the inverse hysteresis model to compensate unknown dynamics of the piezoelectric system. To show the feasibility of the proposed feedforward-feedback controller, some experiments have been carried out and the tracking performance was compared to that of simple PTD controller.

Adaptive Control Method for a Feedforward Amplifier

  • Kang, Sang-Gee;Yi, Hui-Min;Hong, Sung-Yong
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2003.11a
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    • pp.108-112
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    • 2003
  • A feedforward amplifier, which is composed of several components, is an open loop system. Therefore, feedforward amplifiers are apt to deteriorate the performance according to the environmental changes even though the cancellation performance and the linearization bandwidth of feedforward systems are superior to other linearization methods. A control method is needed for maintaining the original performance of feedforward amplifiers or to keep the performance within a little error bounds. In this paper, an adaptive control method, which has a good convergence characteristic and is easy to implement, is suggested. The characteristics of the suggested control method compare with the characteristics of other control methods and the simulation results are presented.

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Improvement of the Characteristics of Feedforward Power Amplifier using Negative Feedback method (Feedback을 첨가한 IMT-2000용 l0W급 Feedforward 선형 전력 증폭기의 설계 및 제작)

  • 류병하;장중호;김성민;최현철
    • Proceedings of the IEEK Conference
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    • 2000.11a
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    • pp.345-348
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    • 2000
  • In this paper, A Feedforward Linear Power Amplifier for IMT-2000 which IMD characteristics was improved was designed and fabricated. To improve the main power amplifier IMD characteristics, the Feedback loop was added to basic Feedforward Power Amplifier structure. Therefore, the output power of error amplifier can be reduced, and it is easy to control the linearization circuit to cancel total IMD. The designed power amplifier represented the 40㏈m(l0W) output power and -55㏈C 3rd IMD at Center frequency 2.14㎓ (@5㎒).

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Rule Based Auto-Tuning PID Controller with Feedforward Path (피드포워드 경로를 갖는 규칙 기반 자동동조 PID제어기)

  • 윤양웅;박왈서
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.41 no.4
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    • pp.355-361
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    • 1992
  • In this paper, some rules for auto- tuning of feedback-feedforward controller in variable load and disturbance are presented. The parameters of feedback PID controller are determined by heuristic rules based on input regulation experiment, and the parameters of feedforward controller are determined by result rules based on spectral factorization, minimum variance, and polynomial equation. These heuristic and result rules are used as an element of the feedback loop in an auto-tuning feedback-feedforward controller. The robust and accurate control performance is demonstrated by computer simulation.

Analysis of the Adaptation Characteristics of the Nulling Loop Control Circuit for the Feedforward Linear Power Amplifier (휘드훠워드 선형 전력 증폭기의 주 신호 제거회로 적응특성해석)

  • Park, Yil;Lee, Sang-Seol
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.10
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    • pp.13-21
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    • 1998
  • In this paper, we analyze the main-carrier cancellation characteristics of the nulling loop control circuit which is used for the main-carrier cancellation circuit of the feedforward linear power amplifier. A new nulling loop error control method is proposed to improve the linear power amplifier characteristics. With this analysis, the main carrier cancellation ratio can be estimated and the required specifications of the main and auxiliary amplifiers can be optimized for the economic and power efficiency.

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Runout Control of a Magnetically Suspended High Speed Spindle Using Adaptive Feedforward Method (적응 Feedforward를 이용한 자기베어링 고속 주축계의 전기적 런아웃 제어)

  • 노승국;경진호;박종권
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.12
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    • pp.57-63
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    • 2002
  • In this paper, the feedforward control with least mean square (LMS) adaptive algorithm is proposed and examined to reduce rotating error by runout of an active magnetic bearing system. Using eddy-current type gap sensor fur control, the electrical runout caused by non-uniform material properties of sensor target produces rotational error amplified in feedback control loop, so this runout should be eliminated to increase rotating accuracy. The adaptive feedforward controller is designed and examined its tracking and stability performances numerically with established frequency response function. The tested grinding spindle system is manufactured with a 5.5 ㎾ internal motor and 5-axis active magnetic bearing system including 5 eddy current gap sensors which have approximately 15 ~ 30 ${\mu}{\textrm}{m}$ of electrical runout. According to the experimental analysis, the error signal in radial bearings is reduced to less than 5 ${\mu}{\textrm}{m}$ when it is rotating up to 50,000 rpm due to applying the feedforward control for first order harmonic frequency, and vibration of the spindle base is also reduced about same frequency.