• Title/Summary/Keyword: Load control

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Development of the Load Curtailment Allocation Algorithm for Load Aggregator in Emergency Demand Response (부하관리사업자의 비상시 부하제어량 배분 알고리즘 개발)

  • 정구형;김진호;김발호
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.53 no.8
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    • pp.466-471
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    • 2004
  • Electricity industries throughout the world are undergoing unprecedented changes. As a result, these changes lead to the separation of traditional integrated utilities and the introduction of competition in order that increase efficiency in electricity industry. Direct load control (DLC) system in competitive electricity market has a hierarchical interactive operation system, therefore, its control logic is also applied by bilateral interactive method that interchanges information related to interruptible load between operation hierarchies. Consequently, load curtailment allocation algorithm appropriate for new DLC system is required, and based on interchanged information, this algorithm should be implemented by most efficient way for each operation hierarchy. In this paper, we develop the load curtailment allocation algorithm in an emergency for new DLC system. Especially, the optimal algorithm for load aggregator (LA) that participates in competitive electricity market as a main operator for load management is developed.

Pole Assignment for Structural Active Control

  • Vongchavalitkul, Sanguan
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.5-7
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    • 2004
  • Significant progress has been achieved in the active control of civil-engineering structures, not only in the control algorithm, but also in control testing of the scaled model and full-scale building. At the present time, most algorithms used in the active control of civil engineering structures are based on the various active control techniques. In this paper represents active control method, by using pole assignment for reducing structural vibration under excited load. Numerical simulations are performed to assess the effectiveness of pole assignment control system. The relative displacement of structure system is significantly reduced.

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Analysis of Load Value acting Free Falling Object according to Disturbance using Nonlinear Load Control Model (비선형 하중 제어 모델에서 외란에 따른 자유낙하 물체에 작용하는 하중값 분석)

  • Wang, Hyeon-Min;Woo, Kwang-Joon
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.47 no.2
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    • pp.55-59
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    • 2010
  • Recently it is tried to use load control model for maneuver moving object. MIN design method proposed to solve control problem of nonlinear system using load concept. The Min design method shows direct method for finding control value on the load control model. In this paper, is shown realization free falling model using nonlinear load control model and analysis of load values acting falling object according to disturbance. And made a trajectory according to acting load values due to disturbance. This paper's result is able to be applied to design algorithm for improvement accuracy of MLRS, GPS air-to-surface missile(ASM) and returning spacecraft with nonlinear model predictive control.

A Improved Programmable-Dynamometer Control For Motor Drive Systems Testing (모터 구동시스템 시험을 위한 개선된 프로그램어블 다이나모메터 제어)

  • 김길동;박현준;조정민;전기영;오봉환;이훈구;한경희
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.52 no.5
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    • pp.211-220
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    • 2003
  • The control method of programmable dynamometer for overall test of machine is to load the reference torque which is computed from torque transducer into motor under test. But the torque information detected from torque transducer have a lot of noise when the load torque of meter is a small quantity or changing. Thus, torque transducer must have a low pass filter to detect a definite torque information. But The torque delay generated by filter with torque transducer occur a torque trouble for meter torque of programmable dynamometer. Therefore, this kind of system could not perform dynamic and nonlinear load. In this paper, the control method using the load torque observer without a measure for torque transducer is Proposed. The proposed system improved the problem of the torque measuring delay with torque transducer, and the load torque is estimated by the minimal order state observer based on the torque component of the vector control induction meter. Therefore, the torque controller is not affected by a load torque disturbance. To verify a superiority of the proposed control algorithm, the analysis for a root locus of a conventional control method and the proposed one, and simulation and experiment is performed. Therefore we hope to be extended in industrial application.

A Study on the Load Frequency Control of 2-Area Power System using Fuzzy-Neural Network Controller (퍼지-신경망 제어기를 이용한 2지역 계통의 부하주파수제어에 관한연구)

  • Chung, Hyeng-Hwan;Kim, Sang-Hyo;Joo, Seok-Min;Lee, Jeong-Phil;Lee, Dong-Chul
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.2
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    • pp.97-106
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    • 1999
  • This paper proposes the structure and the algorithm of the Fuzzy-Neural Controller(FNNC) which is able to adapt itself to unknown plant and the change of circumstances at the Fuzzy Logic Controller(FLC) with the Neural Network. This Learning Fuzzy Logic Controller is made up of Fuzzy Logic controller in charge of a main role and Neural Network of an adaptation in variable circumstances. This construct optimal fuzzy controller applied to the 2-area load frequency control of power system, and then it would examine fitness about parameter variation of plant or variation of circumstances. And it proposes the optimal Scale factor method wsint three preformance functions( E, , U) of system dynamics of load frequency control with error back-propagation learning algorithm. Applying the controller to the model of load frequency control, it is shown that the FNNC method has better rapidity for load disturbance, reduces load frequency maximum deviation and tie line power flow deviation and minimizes reaching and settling time compared to the Optimal Fuzzy Logic Controller(OFLC) and the Optimal Control for optimzation of performance index in past control techniques.

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Experimental Results of Adaptive Load Torque Observer and Robust Precision Position Control of PMSM (PMSM의 정밀 Robust 위치 제어 및 적응형 외란 관측기 적용 연구)

  • Go, Jong-Seon;Yun, Seong-Gu
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.49 no.3
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    • pp.117-123
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    • 2000
  • A new control method for precision robust position control of a PMSM (Permanent Magnet Synchronous Motor) using asymptotically stable adaptive load torque observer is presented in the paper. Precision position control is obtained for the PMSM system approximately linearized using the field-orientation method. Recently, many of these drive systems use the PMSM to avoid backlashes. However, the disadvantages of the motor are high cost and complex control because of nonlinear characteristics. Also, the load torque disturbance directly affects the motor shaft. The application of the load torque observer is published in [1] using fixed gain. However, the motor flux linkage is not exactly known for a load torque observer. There is the problem of uncertainty to obtain very high precision position control. Therefore, a model reference adaptive observer is considered to overcome the problem of unknown parameter and torque disturbance in this paper. The system stability analysis is carried out using Lyapunov stability theorem. As a result, asymptotically stable observer gain can be obtained without affecting the overall system response. The load disturbance detected by the asymptotically stable adaptive observer is compensated by feedforwarding the equivalent current which gives fast response. The experimental results are presented in the paper using DSP TMS320c31.

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Voltage Control of Stand-Alone Inverter for Power Quality Improvement Under Unbalanced and Non-linear Load (불평형 및 비선형부하 시 전력품질 향상을 위한 독립형 인버터의 전압제어 기법)

  • Lee, Wujong;Jo, Jongmin;Cha, Hanju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.4
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    • pp.567-575
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    • 2016
  • This paper proposed the voltage control of stand-alone inverter for power quality improvement under unbalanced and non-linear load. The 3-phase DC-AC inverter controls CVCF(Constant Voltage Constant Frequency) and selective harmonic eliminate method in stand-alone mode by PR controller, and the stand-lone inverter supplies stable sinusoidal voltage to balanced, unbalanced and non-linear loads. The total harmonic distortion(THD) of line-to-line load voltage($V_{LL}$) is 1.2% in the balanced load. THD of $V_{LL}$ is reduced from 5.2% to 1.4% and 6.7% to 3.5%, respectively unbalanced and non-linear load. The stand-alone inverter can be supplies sinusoidal balanced voltage to unbalanced load because the voltage unbalanced factor(VUF) of $V_{LL}$ is reduced from 5.2% to 1.4% in the unbalanced load. Feasibility of control method for a stand-alone inverter will be verified through 30kW stand-alone inverter system.

Characteristic Comparison between PI and Hysteresis Voltage Control of High Voltage Unidirectional Inverter for Piezoelectric Load using FPGA (FPGA를 이용한 피에조 부하 구동용 고전압 단방향 인버터의 PI 및 히스테리시스 전압 제어 특성 비교)

  • Kim, Ki-Seok;Cho, Yong-Ho;Kim, Hyeong-Seop;Kang, Tae-Sam;Hong, Sun-Ki
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.1
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    • pp.48-54
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    • 2017
  • In this paper, hysteresis voltage control method is proposed to an unidirectional inverter control for piezoelectric load. Piezoelectric load has electrically RC characteristic, and is driven by the inverter to control the output voltage waveform. When controling the output waveform by PI control, appropriate gains need to be selected. However, hysteresis control may minimize the output distortion because it has maximum proportional gain. In addition, Hysteresis control algorithm has simple structure to realize and the response is fast. Although the switching frequency of the inverter by hysteresis control varies, the switching frequency for the piezoelectric load is lower than that by PI control for equivalent performance. In particular, on implementing the algorithm using FPGA, the algorithm can be implemented in fewer pabrics and the processing time can be reduced. The superiority of the proposed hysteresis voltage control was proved for piezoelectric load through simulation and experiment.

High performance speed control of induction motor using load torque observer (부하 토오크 관측기를 이용한 유도전동기의 고성능 속도제어)

  • 이성근;임영배;노창주;김윤식
    • Journal of Advanced Marine Engineering and Technology
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    • v.21 no.2
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    • pp.186-194
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    • 1997
  • In this thesis, a new speed control algorithm based on the load torque observer theory is pro¬posed for the high performance speed control of a voltage source inverter to drive a 3 - phase induction motor. The proposed system becomes robust against disturbances using a feed -- for¬ward control of the load torque estimated at load torque observer. Computer simulation and experimental works using the proposed control confirm that transient response for the varia¬tion ofload torque becomes improved, compared with the conventional PI control method.

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Properties of the Load-Sensing Hydraulic System from a Viewpoint of Control (제어관점에서의 부하감지형 유압시스템의 특성)

  • 김성동
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.3
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    • pp.738-750
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    • 1994
  • The load-sensing hydraulic system which was developed to improve energy efficiency of conventional hydraulic systems has its own properties. The instability of system responses, linearity of a servo valve, robustness for variation of external load, and dynamic interference between hydraulic motors are such properties which have much to do with control properties of the system. The load-sensing hydraulic system has instability tendancy because the load-sensing mechanism makes a positive feedback loop between the motor part and the pump part. A flow property of the servo valve can be said to be linear because the flow through the valve has nothing to do with a load pressure and the flow is strictly proportional to a valve opening which is adjusted by a valve command signal. The resultant control property can be said to be robust because the steady-state control performance is independent to the load actuated on the motor shaft. In the case when one pump simultaneously drives more than two hydraulic motors, the pump outlet pressure is determined by a hydraulic motor of the largest load pressure among all of the hydraulic motors, and, thus, the other motors are dominated by the largest load pressure. That is, the other motors can be said to be interfered by the motor of the largest load pressure.