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Subject: search.filters.subject.Phase-locked loop

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    Flow rate controlling using phase-locked loop
    (2013-03-28)
    Prompak, Kriangsak
    ;
    Kaewpoonsuk, Anucha
    ;
    Maneechukate, Thongchai
    ;
    Phanphaisarn, Wasu
    ;
    Wardkein, Paramote
    This paper proposes controlling flow rate by using Phase-Locked Loop (PLL) to control the voltage output of power amplifier sent to the DC pump. With this technique, the flow rate of liquids in the pipe connected to such pump can be easily adjusted. With the property of PLL, the frequency of output signal of the flow sensor, which is proportional to the flow rate, is synchronized with that of the reference input. As a result, the flow rate remains constant. In addition, the experiment results show that the flow rate is not affected by the varying loads, i.e., the flow rate is stable to perturbations. © 2013 ICIC International.
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    Switching frequency control based on phase-locked loop for a current-fed parallel resonant inverter
    (2007-10-01)
    Ponwiangkum, N.
    ;
    Kittiratsatcha, S.
    This paper proposes a computer simulation in PSCAD program of a current-fed parallel resonant inverter. Even though the circuit parameters such as permeability and conductivity have changed regarding to the changing temperature during the heating period. The proposed idea is able to control the phase difference Δθ between the output voltage and output current to be constant at desired value. The principle of the proposed controller utilizes the phaselocked loop with a phase frequency detector. If the Δθ is constant without any effect from the temperature change, then the output power will be controlled precisely by adjusting only the dc-link current. The proposed idea is verified by the experimental results. © 2007 IEEE.
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    A new hybrid fuzzy proportional-derivative phase-locked-loop controller for DC servomotor speed control
    (2007-08-01)
    Sooraksa, Pitikhate
    ;
    Li, Chung Wai
    ;
    Damrongporn, Phuwanat
    Some research work has been heading to the promising direction of enhancing conventional controllers with various powerful intelligent features. In this pursuit, the paper presents a new fuzzy-based phase-locked loop (FPLL) controller for DC servomotor speed control. Fuzzy logic provides fast response and enhances robustness of the system while PLL control gives excellent steady state system performance. Unlike the past literatures, this fuzzy-based controller employs a proportional-derivative (FPD) controller, which is constructed precisely based on rigorous mathematical analysis instead of using look-up tables, with stability guaranteed. Simulation and experimental results have signified the design objectives and been accomplished. The proposed new fuzzy-based PLL controller gives a better dynamic performance compared to a conventional PID controller. Copyright © 2007 Watam Press.
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    PLL equivalent augmented system incorporated with state feedback designed by LQR
    (2007-04-01)
    Wanchana, Somsak
    ;
    Benjanarasuth, Taworn
    ;
    Komine, Noriyuki
    ;
    Ngamwiwit, Jongkol
    The PLL equivalent augmented system incorporated with state feedback is proposed in this paper. The optimal value of filter time constant of loop filter in the phase-locked loop control system and the optimal state feedback gain designed by using linear quadratic regulator approach are derived. This approach allows the PLL control system to employ the large value of the phase-frequency gain K<inf>d</inf> and voltage control oscillator gain K<inf>o</inf>. In designing, the structure of phase-locked loop control system will be rearranged to be a phase-locked loop equivalent augmented system by including the structure of loop filter into the process and by considering the voltage control oscillator as an additional integrator. The designed controller consisting of state feedback gain matrix K and integral gain k<inf>1</inf> is an optimal controller. The integral gain k<inf>1</inf> related to weighting matrices q and R will be an optimal value for assigning the filter time constant of loop filter. The experimental results in controlling the second-order lag pressure process using two types of loop filters show that the system response is fast without steady-state error, the output disturbance effect rejection is fast and the tracking to step changes is good.
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    A high frequency stability of VCO with dual feedback loop
    (2005-12-01)
    Vibunjarone, Vichupong
    ;
    Prempraneerach, Yothin
    This paper is purposed to improve the high frequency stability of the voltage controlled oscillator (VCO) with dual feedback loop. The proposed of closed loop VCO (CLVCO) is composed of PI controller in the forward part and in the feedback part the phase locked loop is used instead of a frequency to voltage converter (FVC) for some advantages, there is no need for a large frequency division element (1/N) in the feedback part. The other advantages of phase-locked loop is used as the feedback element, the high frequency bandwidth of a closed loop VCO is possibly designed. The CLVCO can greatly improved VCO characteristic such as faster speed response as well as higher operation bandwidth, to minimize the effect of the VCO noise and the power supply variation and also obtain better linearity of VCO output. The experimental results confirm the validity of the proposed CLVCO. © 2005 SICE.
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    A new phase-locked loop system with the controllable output phase and the lock up time
    (2005-12-01)
    Vibunjarone, Vichupong
    ;
    Prempraneerach, Yothin
    This paper, we propose a new phase-locked loop (PLL) system with controllable the output phase independent from the output frequency and lock-up time. This PLL system has a dual control loop is described, the inner loop greatly improves VCO characteristic. The main loop is the heart of this PLL, which greatly improves the output frequency instability due to the external high frequency noise coupling to the input reference frequency. This main loop has the two control inputs, the first one achieves to control the output frequency of the VCO and the other one is used to control the output phase independently from the frequency output as well as the lock-up time which can be controlled for optimum output response by this input. The experimental results confirm the validity of the proposed phase-locked loop. © 2005 SICE.