• Title, Summary, Keyword: Output voltage stabilization

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Secondary Side Output Voltage Stabilization of an IPT System by Tuning/Detuning through a Serial Tuned DC Voltage-controlled Variable Capacitor

  • Tian, Jianlong;Hu, Aiguo Patrick;Nguang, Sing Kiong
    • Journal of Power Electronics
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    • v.17 no.2
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    • pp.570-578
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    • 2017
  • This paper proposes a method to stabilize the output voltage of the secondary side of an Inductive Power Transfer (IPT) system through tuning/detuning via a serial tuned DC Voltage-controlled Variable Capacitor (DVVC). The equivalent capacitance of the DVVC changes with the conduction period of a diode in the DVVC controlled by DC voltage. The output voltage of an IPT system can be made constant when this DVVC is used as a variable resonant capacitor combined with a PI controller generating DC control voltage according to the fluctuations of the output voltage. Since a passive diode instead of an active switch is used in the DVVC, there are no active switch driving problems such as a separate voltage source or gate drivers, which makes the DVVC especially advantageous when used at the secondary side of an IPT system. Moreover, since the equivalent capacitance of the DVVC can be controlled smoothly with a DC voltage and the passive diode generates less EMI than active switches, the DVVC has the potential to be used at much higher frequencies than traditional switch mode capacitors.

An Electronic Step-Down Transformer with Voltage Stabilization Characteristics for Custom Power (전압 안정화 특성을 갖는 수용가용 전자식 강압형 변압기)

  • 최남섭;강정식
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.423-426
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    • 2001
  • In this paper, an electronic step-down transformer with output voltage stabilization characteristics is presented. The proposed electronic transformer has some advantages and features as follows: 1) It has 40 % weights lighter than that of commercial magnetic transformer, 2) It has output voltage stabilization characteristic with regulated output voltage over input variations, 3) It cab be operated as circuit breaker in the case of emergency, 4) It can be operated with so called soft starting function. Moreover, the electronic transformer may have stand-by power cutoff function and act as distortion compensator. This paper show the circuit diagram and present its features through various PSPICE simulations.

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A Study on the Output Stabilization of the Nd:YAG Laser by the Monitoring of Capacitor Charging Voltage

  • Noh, Ki-Kyong;Song, Kum-Young;Park, Jin-Young;Hong, Jung-Hwan;Park, Sung-Joon;Kim, Hee-Je
    • KIEE International Transactions on Electrophysics and Applications
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    • v.4C no.3
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    • pp.96-100
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    • 2004
  • The Nd: YAG laser is commonly used throughout many fields such as accurate material processing, IC marking, semiconductor annealing, medical operation devices, etc., due to the fact that it has good thermal and mechanical properties and is easy to maintain. In materials processing, it is essential to vary the laser power density for specific materials. The laser power density can be mainly controlled by the current pulse width and pulse repetition rate. It is important to control the laser energy in those fields using a pulsed laser. In this paper we propose the constant-frequency current resonant half-bridge converter and monitoring of capacitor charging voltage. This laser power supply is designed and fabricated to have less switching loss, compact size, isolation with primary and secondary transformers, and detection of capacitor charging voltage. Also, the output stabilization characteristics of this Nd: YAG laser system are investigated. The test results are described as a function of laser output energy and flashlamp arc discharging constant. At the energy storage capacitor charges constant voltage, the laser output power is 2.3% error range in 600[V].

A Multifunctional Three-Phase Electronic Step-Down Transformer with Constant Output Voltage Characteristics (정전압 출력 특성을 갖는 다기능 3상 전자식 강압형 변압기)

  • 최남섭
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.5 no.2
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    • pp.309-313
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    • 2001
  • In this paper, a multifunctional three-phase electronic step-down transformer with output voltage stabilization characteristics is presented for custom power applications. The proposed electronic transformer has some advantages and features as follows: 1) It has 40 % weights lighter than that of commercial magnetic transformer, 2) It has output voltage stabilization characteristic with regulated output voltage over input variations, 3) It cab be operated as circuit breaker in the case of emergency, 4) It can be operated with so called soft starting function. Moreover, the electronic transformer may have stand-by power cutoff function and act as distortion compensator. This paper show the circuit diagram and present its features through various PSPICE simulations.

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Design of an Adaptive Fuzzy Controller for Power System Stabilization

  • Park, Young-Hwan;Park, Jang-Hyun;Yoon, Tae-Woong;Park, Gwi-Tae
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • pp.432-437
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    • 1998
  • Power systems have uncertain dynamics due to a variety of effects such as lightning, severe storms and equipment failures. The variation of the effective reactance of a transmission line due to a fault is an example of uncertainty in power system dynamics. Hence, a robust controller to cope with these uncertainties is needed. Recently fuzzy controllers have become quite popular for robust control due to its capability of dealing with unstructured uncertainty. Thus in this paper we design an adaptive fuzzy controller using an input-output linearization approach for the transient stabilization and voltage regulation of a power system under a sudden fault. Simulation results show that satisfactory performance is achieved by the proposed controller.

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Operation modes and Protection of VS(Vertical Stabilization) Converter for International Thermonuclear Experimental Reactor (국제 핵융합실험로용 VS(Vertical Stabilization) 컨버터의 운전모드 및 보호동작)

  • Jo, Hyunsik;Jo, Jongmin;Oh, Jong-Seok;Suh, Jae-Hak;Cha, Hanju
    • The Transactions of the Korean Institute of Power Electronics
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    • v.20 no.2
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    • pp.130-136
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    • 2015
  • This study describes the structure and operation modes of vertical stabilization (VS) converter for international thermonuclear experimental reactor (ITER) and proposes a protection method. ITER VS converter supplies voltage (${\pm}1000V$)/current (${\pm}22.5kA$) to superconducting magnets for plasma current vertical stabilization. A four-quadrant operation must be achieved without zero-current discontinuous section. The operation mode of the VS converter is separated in 12-pulse mode, 6-pulse mode and circulation current mode according to the magnitude of the load current. Protection measures, such as bypass and discharge, are proposed for abnormal conditions, such as over current, over voltage, short circuit, and voltage sag. VS converter output voltage is controlled to satisfy voltage response time within 20 msec. Bypass operation is completed within 60 msec and discharge operation is performed successfully. The feasibility of the proposed control algorithm and protection measure is verified by assembling a real controller and implementing a power system including the VS converter in RTDS for a hardware-in-loop (HIL) facility.

Comparative Analysis of Sequence Control in Six Series-Connected ITER VS Converters (6 직렬 연결된 ITER VS 컨버터의 시퀀스제어 비교 해석)

  • Jo, Hyunsik;Jeong, Jinyong;Jo, Jongmin;Cha, Hanju
    • The Transactions of the Korean Institute of Power Electronics
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    • v.19 no.5
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    • pp.399-406
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    • 2014
  • This study investigates the structure and operation of the ITER VS converter and proposes a sequence control method for six series-connected VS converters to reduce reactive power. The operation and the proposed sequence control method are verified through RTDS simulation. The ITER VS converter must supply voltage/current to the superconducting magnets for plasma current vertical stabilization, and the four-quadrant operation must proceed without a zero-current discontinuous section. The operation mode of the VS converter is separated into a 12- and 6-pulse circulating current and transition modes according to the size of the load current. The output voltage of the unit VS converter is limited because of the rated voltage; however, the superconducting coil must increase the operating output voltage. Thus, the VS converter must be connected in a 6-series to provide the required operating output voltage. The output voltage of the VS converters is controlled continuously; however, reactive power is limited within a minimized value of the grid. In this study, the unit converter is compared with converters connected in a 6-series to determine a suitable sequence control method. The output voltage is the same in all cases, but the maximum reactive power is reduced from 100% to 73%. This sequence control method is verified through RTDS simulation.

Nonlinear Input-Output Feedback Linearizing Control for Power System Stabilization (전력계통 안정화를 위한 비선형 입출력 궤환 선형화 제어기)

  • Kim, Dong-Gun;Yoon, Tae-Woong
    • Proceedings of the KIEE Conference
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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.

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Operational Characteristics of a Flux-Lock Type SFCL Integrated with Voltage-Controlled Voltage Source Inverter

  • Lee, Su-Won;Lim, Sung-Hun;Ko, Sung-Hun;Lee, Seong-Ryong
    • Journal of Electrical Engineering and Technology
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    • v.3 no.4
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    • pp.546-551
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    • 2008
  • In this paper, a flux-lock type superconducting fault current limiter(SFCL) integrated with a voltage-controlled voltage source inverter(VC-VSI) is proposed. The suggested equipment, which consists of a flux-lock type SFCL and a VCVSI, can perform the fault current limiting operation from the occurrence of a short-circuit. In addition, it can compensate the reactive power that the non-linear load requires and also perform the uninterruptible power supply(UPS) as well as the load voltage stabilization by controlling the amplitude and the phase of the inverter's output voltage. The specification for a test model was determined and its various functions such as the fault current limiting and the power conditioning operations were presented and analyzed via computer simulation. Through the analytical results based on the computer simulation, the validity of the analysis was confirmed and its multi-operation was discussed.

Sensorless Passivity Based Control of a DC Motor via a Solar Powered Sepic Converter-Full Bridge Combination

  • Linares-Flores, Jesus;Sira-Ramirez, Hebertt;Cuevas-Lopez, Edel F.;Contreras-Ordaz, Marco A.
    • Journal of Power Electronics
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    • v.11 no.5
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    • pp.743-750
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    • 2011
  • This article deals with the sensor-less control of a DC Motor via a SEPIC Converter-Full Bridge combination powered through solar panels. We simultaneously regulate, both, the output voltage of the SEPIC-converter to a value larger than the solar panel output voltage, and the shaft angular velocity, in any of the turning senses, so that it tracks a pre-specified constant reference. The main result of our proposed control scheme is an efficient linear controller obtained via Lyapunov. This controller is based on measurements of the converter currents and voltages, and the DC motor armature current. The control law is derived using an exact stabilization error dynamics model, from which a static linear passive feedback control law is derived. All values of the constant references are parameterized in terms of the equilibrium point of the multivariable system: the SEPIC converter desired output voltage, the solar panel output voltage at its Maximun Power Point (MPP), and the DC motor desired constant angular velocity. The switched control realization of the designed average continuous feedback control law is accomplished by means of a, discrete-valued, Pulse Width Modulation (PWM). Experimental results are presented demonstrating the viability of our proposal.