• Title/Summary/Keyword: Voltage controller

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Three-Phase 4-Wire Isolated Wind Energy Conversion System Employing VSC with a T-Connected Transformer for Neutral Current Compensation

  • Kasal, Gaurav Kumar;Singh, Bhim
    • Journal of Electrical Engineering and Technology
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    • v.4 no.2
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    • pp.211-218
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    • 2009
  • This paper presents a voltage and frequency controller (VFC) for a 4-wire stand-alone wind energy conversion system (WECS) employing an asynchronous generator. The proposed VF con-troller consists of a three leg IGBT (Insulated Gate Bipolar Junction Transistor) based voltage source converter and a battery at its DC bus. The neutral terminal for the consumer loads is created using a T-connected transformer, which consists of only two single phase transformers. The control algorithm of the VF controller is developed for the bidirectional flow capability of the active power and reactive power control by which it controls the WECS voltage and frequency under different dynamic conditions, such as varying consumer loads and varying wind speeds. The WECS is modeled and simulated in MATLAB using Simulink and PSB toolboxes. Extensive results are presented to demonstrate the capability of the VF controller as a harmonic eliminator, a load balancer, a neutral current compensator as well as a voltage and frequency controller.

Grid Connected Inverter of ESS for Seamless mode Transition (분산 발전 시스템에서 계통연계 인버터의 매끄러운 모드 전환)

  • Hong, Chang-Pyo;Kim, Hag-Wone;Cho, Kwan-Yuhl
    • The Transactions of the Korean Institute of Power Electronics
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    • v.21 no.4
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    • pp.364-372
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    • 2016
  • In this paper, a voltage controller for the seamless transition of a grid-connected inverter for ESS is proposed. The single-phase inverter is operated as a current controller when the grid is connected and as a voltage controller in the stand-alone mode when the grid is disconnected. Generally, in the case of grid recovery, the overcurrent may flow into the system because of the mismatch phase between the inverter output and grid voltages. The proposed controller resolves the overcurrent problem through phase delay problems with initial value feed-forward control of the integrator when the grid voltage is restored. The effects of the control method are simulated through PSIM, and the usefulness of the control method is verified through experiments.

Robust Control of DC-DC Converter by Approximate 2DOF Digital Controller Realizing First-Order Model

  • Higuch, Kohji;Takegami, Eiji;Nakano, Kazushi;Tomioka, Satoshi;Watanabe, Kazushi
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.794-799
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    • 2005
  • Robust DC-DC converter which can cover extensive load changes and also input voltage changes with one controller is needed. In this paper, we propose a method for determining the parameters of 2DOF digital controller which makes the control bandwidth wider, and at the same time makes a variation of the output voltage very small at sudden changes of resistive load and the input voltage. The 2DOF digital controller whose parameters are determined by the proposed method is actually implemented on a DSP and is connected to a DC-DC converter. Experimental studies demonstrate that this type of digital controller can satisfy given specifications.

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A Controller Design for a Stability Improvement of an On-Board Battery Charger

  • Jeong, Hae-Gwang;Lee, Kyo-Beum
    • Journal of Electrical Engineering and Technology
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    • v.8 no.4
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    • pp.951-958
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    • 2013
  • This paper proposes the controller design for a stability improvement of an on-board battery charger. The system is comprised of a power factor correction (PFC) circuit and phase shift full-bridge DC-DC converter. The PFC circuit performs the control of the DC-link voltage and the input power factor. The DC-DC converter regulates the voltage and the current in the battery using the DC-link voltage. This paper proposes the design method of PI controller for the PFC circuit using a small signal model. The analysis and design of a type-three controller for the DC-DC converter is also presented. A simulation and experiment has been performed on the on-board battery charger and their results are presented to verify the validity of the proposed system.

ANN-based Maximum Power Point Tracking of PV System using Fuzzy Controller (퍼지 제어기를 이용한 PV 시스템의 ANN 기반 최대전력점 추적)

  • Ko, Jae-Sub;Chung, Dong-Hwa
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.2
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    • pp.27-32
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    • 2015
  • A maximum power point tracking (MPPT) algorithm using fuzzy controller was considered. MPPT method was implemented based on the voltage and reference PV voltage value was obtained from Artificial Neural Network (ANN)-model of PV modules. Therefore, measuring only the PV module voltage is adequate for MPPT operation. Fuzzy controller is used to directly control dc-dc buck converter. The simulation results have been used to verify the effectiveness of the algorithm. The proposed method is compared with conventional PO(perturbation & observation), IC(Incremental Conductance) method. The nonlinearity and adaptiveness of fuzzy controller provided good performance under parameter variations such as solar irradiation.

Voltage Control Scheme in Synchronous Reference Frame for Improving Dynamic Characteristics in Parallel Operation of Double-Conversion UPSs (이중 변환 UPS 병렬 운전의 제어 동특성 향상을 위한 동기 좌표계 전압 제어기 구조)

  • Mo, Jae-Sing;Yoon, Young-Doo;Ryu, Hyo-Jun;Lee, Min-Sung;Choi, Seung-Cheul;Kim, Sung-Min;Kim, Seok-Min;Kang, Ho-Hyun;Kim, Hee-Jung
    • The Transactions of the Korean Institute of Power Electronics
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    • v.27 no.4
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    • pp.283-290
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    • 2022
  • This study proposes a voltage control scheme in a synchronous reference frame to improve the dynamic characteristics of double-conversion UPSs. UPSs need to control positive and negative sequence voltage, so that positive and negative sequence extractors are generally used to obtain each sequence of the voltage and current. Voltage and current controllers for each sequence are implemented. However, the extractor causes considerable delay, and the delay restricts the control performance, especially for the current controller. To improve the dynamics of the current controller, the proposed scheme adopts a unified current controller without separating positive and negative sequences. By using discrete-time current controller, the control bandwidth can be extended significantly so that negative sequence current can be controlled. To enhance the performance, an additional feed-forward technique for output voltage regulation is proposed. The validity of the proposed controller is verified by experiments.

Design of the Robust Hybrid Controller for Three-Phase Four-Leg Voltage Source Inverter under the Unbalance Load (불평형 부하에서 강인한 3상4족 전압형 인버터를 위한 하이브리드 제어기의 설계)

  • Doan, Van-Tuan;Choi, Woojin
    • Proceedings of the KIPE Conference
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    • 2014.07a
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    • pp.291-292
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    • 2014
  • The three-phase four-leg voltage source inverter (VSI) topology can be an interesting option for the three phase-four wire system. With an additional leg, this topology can achieve superior performance with unbalanced and/or nonlinear load. This paper proposes a new hybrid controller which combines PI controller and resonant controller in synchronous frame for three phase four leg inverter. The hybrid controller is simple in structure and easy to implement. The performance of proposed controller is verified by the experiments and compared with that of the conventional PI controller.

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Repetitive Controller Design to Reduce THD of an AC Power Supply (AC 전원장치의 출력 THD저감을 위한 반복제어기 설계)

  • 김병진;최재호
    • Proceedings of the KIPE Conference
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    • 1999.07a
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    • pp.311-314
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    • 1999
  • This paper presents the design method of a repetitive controller to educe the harmonics in the output voltage waveform of the AC power supply systems. Output voltage error under the nonlinear load like a rectifier is cyclic with the same period to fundamental wave, therefore one can design the repetitive controller calculating cycle by cycle. The controller is verified mathematically and by simulations.

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Voltage Controller Design of Synchronous Generator by Pole Assignment (극배치에 의한 동기발전기의 전압제어기 설계)

  • Yim, Han-Suck
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.34 no.12
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    • pp.472-484
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    • 1985
  • A design of robust voltage controller for high speed excitation of synchronous machine was carried out by pole assignment techniques. An affine map from characteristic polynomial coefficients to feedback parameters is formulated in order to place the system eigen values in the desired region. The feedback parameters determined from linearized model are tested on nonlinear model subjecting it to small disturbances and system faults to show the effectiveness of the controller designed by the proposed technique. The results obtained indicate that the controller presented improves the dynamic stability and system performances of conventionally controlled synchronous machine significantly.

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PFC Controller Design for 3-Phase Modular UPS (3상 모듈형 UPS용 PFC 제어기 설계)

  • Park, Nae Chun;Kim, Sang Hoon;Ji, Jun Keun
    • Proceedings of the KIPE Conference
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    • 2010.11a
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    • pp.44-45
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    • 2010
  • In this paper a new PFC Controller for 3-Phase Modular UPS is proposed. The PFC circuit for 3-Phase Modular UPS is implemented using three 1-phase 3-level boost PFC circuits. To control DC output voltage and AC input current, single voltage controller considering imbalance of two capacitor voltages and three independent current controllers are used in proposed PFC controller.

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