• 제목/요약/키워드: Carrier Control

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Performance Comparison of Single-Carrier and Multi-Carrier Systems in a Terahertz Wireless Communication Environment

  • Asiedu, Derek Kwaku Pobi;Ahiadormey, Roger Kwao;Shin, Suho;Lee, Kyoung-Jae
    • Journal of Advanced Information Technology and Convergence
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    • v.9 no.1
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    • pp.11-24
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    • 2019
  • This paper investigates the performance comparison of a Terahertz (THz) communications for a single-carrier and a multi-carrier single antenna point-to-point communication system. The multi-carrier system and single carrier system consider the orthogonal frequency division multiplexing (OFDM) and the minimum mean square error linear equalizer (MMSE-LE), respectively. We compare the frame-error-rate (FER) and throughput performance of both the systems for a THz communication environment with the carrier frequency of 300GHz and the tapped delay line (TDL) channel models described in 3GPP. It is observed from the simulation results that the OFDM systems outperform the MMSE-LE for various configurations.

The Effect of Asynchronous Carrier on Matrix Converter Characteristics

  • Oyama, Jun;Higuchi, Tsuyoshi;Abe, Takashi;Yamada, Eiji;Hayashi, Hideki;Koga, Takashi
    • Proceedings of the KIPE Conference
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    • 1998.10a
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    • pp.512-517
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    • 1998
  • In a matrix converter, input side and output side are coupled with each other through switching elements. Since disturbances on either side affect directly on the other side, it requires a high-speed on-line control system to compensate them. We proposed in previous papers a new control strategy and an on-line control circuit for a matrix converter. The control circuit could keep the output voltage at commanded value against fluctuation in the supply voltage. Furthermore wave forms of the output voltage and the input current were always kept sinusoidal. The switching pattern was generated by comparing modified voltage references with a carrier. The carrier was synchronized with the supply voltage using a PLL system, which made the control circuit complicated and costly. This paper discusses on the possibility of an asynchronized carrier. Experiment results show the input current distortion in case of asynchronous carrier is bigger than that of synchronous carrier. However, the deterioration can be minimized by increased carrier frequency.

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A single-carrier comparison PWM for Voltage Control of Vienna Rectifier (단일 반송파를 이용한 비엔나 정류기의 전압 제어)

  • Yoon, Byung-Chul;Kim, Hag-Wone;Cho, Kwan-Yuhl;Lim, Byung-Kuk
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.2
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    • pp.129-134
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    • 2012
  • In this paper, a new simple PWM method for Vienna rectifier is proposed. The previous SVPWM method for Vienna rectifier is very complex and difficult to implement. To solve these problems, a new single-carrier comparison PWM method for voltage control of Vienna rectifier is proposed. Because of using the only single carrier, implementation of the proposed PWM is very simple. In the proposed PWM method, carrier comparison parts of the PWM block is only changed from the 2 level PWM control block. The usefulness of the proposed PWM method is verified by the simulation and experiment.

Guidance and Control System Design for Automatic Carrier Landing of a UAV (무인 항공기의 함상 자동 착륙을 위한 유도제어 시스템 설계)

  • Koo, Soyeon;Lee, Dongwoo;Kim, Kijoon;Ra, Chung-Gil;Kim, Seungkeun;Suk, Jinyoung
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.11
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    • pp.1085-1091
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    • 2014
  • This paper presents the guidance and control design for automatic carrier landing of a UAV (Unmanned Aerial Vehicle). Differently from automatic landing on a runway on the ground, the motion of a carrier deck is not fixed and affected by external factors such as ship movement and sea state. For this reason, robust guidance/control law is required for safe shipboard landing by taking the relative geometry between the UAV and the carrier deck into account. In this work, linear quadratic optimal controller and longitudinal/lateral trajectory tracking guidance algorithm are developed based on a linear UAV model. The feasibility of the proposed control scheme and guidance law for the carrier landing are verified via numerical simulations using X-Plane and Matlab/simulink.

The computation algorithm for angular rate using GPS carrier phase (GPS의 반송파 위상을 이용한 각속도 계산 알고리즘)

  • 박준구;김진원;이장규
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.1338-1341
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    • 1997
  • In this paper, we propose angular rate computation algorithm using GPS carrier phase. A direct angylar rate masurement has not previously been available form GRS, although its availability is highly desirable for use in state feedback control. So we propose angular rate computationalgorithm which derive angular rate from the velocity of differentiated carrier phase og GPS. The proposed algorithm contains attitude determination using double-differentiated carrier phase and 2 baseline configuration whcih provide more practical applications than 3 baseline.

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An Improved Saw Tooth Carrier PWM Method for Three Phase Voltage Source Inverters (3상 전압원 인버터를 위한 개선된 톱니 반송파 펄스 폭 변조 방법)

  • Park, In-Gyu
    • Proceedings of the KIEE Conference
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    • 1995.11a
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    • pp.302-305
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    • 1995
  • An improved carrier PWM method for three phase voltage source inverters is proposed. The basic idea of the proposed method is deleting unnecessary 1/3 of switchings in the saw tooth carrier PWM method. The lowest frequency of the remained harmonics of this method (when the modulation index is large) is about 50% higher and the maximum modulated voltage is about 15% higher than those of the triangular carrier PWM method. This method will be useful especially in the linear feedback current control and MOSFET inverters.

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Passive Maglev Carrier Control with Consideration of Pitch Motion (피치 운동을 고려한 자기부상 수동형 이송자 제어)

  • Lee, Younghak;Kim, Chang-Hyun;Ha, Chang-Wan;Park, Doh-Young;Yang, Seok-Jo;Lim, Jaewon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.2
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    • pp.213-220
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    • 2016
  • This research aims to develop core technologies for passive carrier (no power in carrier itself) transfer system. The technologies are passive levitation, propulsion, and guidance, which can be great benefits for semiconductor and display manufacturing industries. Passive maglev carrier is necessary to precise position control for quiet and stable transfer operation. However, the structural characteristics of carrier and the installation errors of gap sensors cause the pitch motion. Hence, the controller design in consideration of pitch motion is required. This study deals with the reduction control of carrier pitch motion. PDA controller and PDA controller with pitch control are proposed to compare the pitch angle analysis. The pitch angle and the levitation precision are measured by experiment. Finally, the optimized design of pitch controller is presented and the effects are discussed.

Carrier Tracking Loop using the Adaptive Two-Stage Kalman Filter for High Dynamic Situations

  • Kim, Kwang-Hoon;Jee, Gyu-In;Song, Jong-Hwa
    • International Journal of Control, Automation, and Systems
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    • v.6 no.6
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    • pp.948-953
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    • 2008
  • In high dynamic situations, the GPS carrier tracking loop requires a wide bandwidth to track a carrier signal because the Doppler frequency changes more rapidly with time. However, a wide bandwidth allows noises within the bandwidth of the tracking loop to pass through the loop filter. As these noises are used in the numerical controlled oscillator(NCO), the carrier tracking loop of a GPS receiver shows a degraded performance in high dynamic situations. To solve this problem, an adaptive two-stage Kalman filter, which offers the NCO a less noisy phase error, can be used. This filter is based on a carrier phase dynamic model and can adapt to an incomplete dynamic model and a quickly changed Doppler frequency. The performance of the proposed tracking loop is verified by several simulations.

A New Carrier Recovery Algorithm Usign $\theta$-matching method for QAM Demodulator ($\theta$-정합을 이용한 QAM 복조용 Carrier Recovery)

  • 박휘원;장일순정차근조경록
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.179-182
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    • 1998
  • Carrier recovery, the process of recoverying the carrier in receiver, removes the phase difference between VCO and the received signal. However, the conventional structure of carrier recovery cannot be applied to multi-level QAM demodulator because of the increasing decision interval and the complexity of control as the number of symbol increases. In this paper, we suggest a new carrier recovery algorithm using $\theta-matching$ algorithm for multi-level QAM demodulation to overcome this problem and analysis the performance and implement it.

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PWM Method with Low d-axis Current Ripple for reducing Input Current THD at Light Loads in Three Phase PWM Rectifier (3상 PWM 정류기의 경부하시 입력전류 THD 저감을 위한 d축 전류리플 저감 PWM 방법)

  • Jin, Yong-Sin;Shin, Hee-Keun;Kim, Hag-Wone;Cho, Kwan-Yuhl
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.6
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    • pp.478-485
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    • 2012
  • In this paper, a new PWM method is proposed to reduce the input current harmonics of 3 phase PWM rectifier. In the conventional carrier comparison PWM method, a triangular wave is generally used as the carrier wave. However, the large d-axis current ripple by the triangle carrier wave may be a source of large input current THD(Total Harmonic Distortion). In this paper, a new carrier comparison PWM method with saw tooth wave is proposed. Depending on the sector where the voltage command vector places, one of the rising or falling saw tooth wave is selected. To reduce the switching losses of the saw tooth carrier PWM, the discontinuous PWM is also presented. The proposed PWM method can reduce the d-axis current ripple as well as the switching losses. The performance of the conventional and proposed PWM methods is verified by the simulation and experimental results.