• Title/Summary/Keyword: multi variable control

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A study on application of aggregation method based on power flow matching technique and multi-variable control method to the power system (선로 조류 유지 기법에 근거한 계통축약 및 다변수 제어기법 적용 연구)

  • Lee, Byung-Ha;Oh, Min-Hyuk;Baek, Jung-Myoung
    • Proceedings of the KIEE Conference
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    • 2006.11a
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    • pp.342-344
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    • 2006
  • The modem enormous electric power system has made power system analysis much more complex and difficult. For effective analysis of the power system, model reduction and aggregation is required. In this paper, a new aggregation method is presented to aggregate the coherent generators in the large scale power system while matching the power flow. In order to demonstrate the effects of this aggregation method, it is applied to a small scale power system. A multi-variable control technique of $H_{\infty}$ control is also applied to enhance the dynamic stability of the aggregated power system.

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Vibration Control of a Flexible Two-link Manipulator based on the Sliding Mode Control (슬라이딩 모우드 제어에 기초한 유연한 2링크 조작기의 진동제어)

  • Chae, Seung-Hoon;Yang, Hyun-Seok;Park, Young-Phil
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.511-516
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    • 2000
  • In order to not only perform as a extreme model under the severe operating condition but also acquire more diverse and advanced control capability utilizing high compliance, active vibration control of a flexible 2-link robot manipulator are investigated. Multi variable-structured frequency shaped optimal sliding mode is proposed for the flexible robot manipulator like control system, whose control variables, an angular motion of joint and vibration of flexible link, have to be controlled simultaneously by one control torque at a driving joint. The control system is divided into two subsystems, a control input related subsystem and an added subsystem. The proposed sliding mode, composed of multi control variables, makes optimized relation between subsystems and a individual control input, thus, the sliding mode controller can compensate whole dynamics of each subsystems simultaneously. And the possibility and effectiveness are verified by vibration control of a manipulator having two flexible links. Simulation and experiment results show that the proposed control scheme achieves the purpose effectively.

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Multi-function Control of Hydraulic Variable Displacement Pump with EPPR Valve (전자비례감압밸브를 이용한 가변용량형 유압펌프의 다기능 제어)

  • Jung, Dong-Soo;Kim, Hyong-Eui;Kang, E-Sok
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.6
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    • pp.160-170
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    • 2006
  • If hydraulic pump controlled by mechanical type regulator has more than one control function, the construction of regulator will be very complicated and control performance falls drastically. It is difficult to have more than one control function for hydraulic pump controlled by electronic type hydraulic valve due to the inconsistency of controllers. This paper proposes a multi-function control technique which controls continuously flow, pressure and power by using EPPR(Electronic Proportional Pressure Reducing) valve in swash plate type axial piston pump. Nonlinear mathematical model is developed from the continuity equation for the pressurized control volume and the torque balance for the swash plate motion. To simplify the model we make the linear state equation by differentiating the nonlinear model. A reaction spring is installed in servo cylinder to secure the stability of the control system. We analyze the stability and disturbance by using the state variable model. Finally, we review the control performances of flow, pressure and power by tests using PID controller.

A robust multi-objective localized outrigger layout assessment model under variable connecting control node and space deposition

  • Lee, Dongkyu;Lee, Jaehong;Kang, Joowon
    • Steel and Composite Structures
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    • v.33 no.6
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    • pp.767-776
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    • 2019
  • In this article, a simple and robust multi-objective assessment method to control design angles and node positions connected among steel outrigger truss members is proposed to approve both structural safety and economical cost. For given outrigger member layouts, the present method utilizes general-purpose prototypes of outrigger members, having resistance to withstand lateral load effects directly applied to tall buildings, which conform to variable connecting node and design space deposition. Outrigger layouts are set into several initial design conditions of height to width of an arbitrary given design space, i.e., variable design space. And then they are assessed in terms of a proposed multi-objective function optimizing both minimal total displacement and material quantity subjected to design impact factor indicating the importance of objectives. To evaluate the proposed multi-objective function, an analysis model uses a modified Maxwell-Mohr method, and an optimization model is defined by a ground structure assuming arbitrary discrete straight members. It provides a new robust assessment model from a local design point of view, as it may produce specific optimal prototypes of outrigger layouts corresponding to arbitrary height and width ratio of design space. Numerical examples verify the validity and robustness of the present assessment method for controlling prototypes of outrigger truss members considering a multi-objective optimization achieving structural safety and material cost.

Alleviating the Tower Mechanical Load of Multi-MW Wind Turbines with LQR Control

  • Nam, Yoonsu;Kien, Pham Trung;La, Yo-Han
    • Journal of Power Electronics
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    • v.13 no.6
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    • pp.1024-1031
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    • 2013
  • This paper addresses linear quadratic regulation (LQR) for variable speed variable pitch wind turbines. Because of the inherent nonlinearity of wind turbines, a set of operating conditions is identified and then a LQR controller is designed for each of the operating points. The feedback controller gains are then interpolated linearly to get a control law for the entire operating region. In addition, the aerodynamic torque and effective wind speed are estimated online to get the gain-scheduling variable for implementing the controller. The potential of this method is verified through simulation with the help of MATLAB/Simulink and GH Bladed. The performance and mechanical load when using LQR are also compared with those obtained when using a PI controller.

MIMO Variable Structure Control System with Sliding Sector (슬라이딩 섹터를 갖는 다중 입출력 가변 구조 제어 시스템)

  • Choi Han-Ho
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.6
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    • pp.524-529
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    • 2006
  • In this paper, we propose a method to design variable structure systems with sliding sector for multi-input multi-output systems with mismatched uncertainties in the state matrix. For the uncertain systems we define sliding sectors within which a norm of the state decreases with zero input despite of mismatched uncertainties. Using the notion of the sliding sector we give simple design algorithms of variable structure control laws that can reduce the chattering. Finally, we give a design example in order to show the effectiveness of our method.

An Experimental Study on Variable-Speed Control of an Ground-Water Circulation Pump for a Ground Source Multi-Heat Pump System (주거용 건물 지열원 멀티 히트펌프시스템의 지열순환펌프 가변유량제어에 관한 실증연구)

  • Song, Suwon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.25 no.8
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    • pp.443-449
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    • 2013
  • The purpose of this study is to propose an enhanced variable-speed control method of ground-water circulation pumps using inlet and outlet ground-water temperature difference and analyze its effect for the ground source multi-heat pump system installed in a single-family house. As a result, it has shown to significantly reduce the electricity use of ground-water circulation pump and improve overall system Coefficient of Performance (COP) due to the proposed variable-speed control under partial load conditions after oversized and inefficient single-speed pump retrofit.

An Improved Voltage Control Scheme for DC-Link Voltage Balancing in a Four-Level Inverter (4-레벨 인버터의 DC-링크 전압 균형을 위한 향상된 전압 제어 기법)

  • Kim, Rae-Yeong;Lee, Yo-Han;Choe, Chang-Ho;Hyeon, Dong-Seok
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.48 no.10
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    • pp.544-554
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    • 1999
  • Multi-level inverters are now receiving widespread interest form the industrial drives for high power variable speed applications. Especially, for the high power variable speed applications, a diode clamped multi-level inverter has been widely used. However, it has the inherent problem that the voltage of the link capacitors fluctuates. This paper describes a voltage control scheme effectively to suppress the DC-link potential fluctuation for a diode clamped four-level inverter. The current to flow from/into the each link capacitor is analyzed and the operation limit is obtained when a conventional SVPWM is used. To overcome the operation limit, a modified carrier-based SVPWM is proposed. Various simulation and experiment results are presented to verify the proposed voltage control scheme for DC-link voltage balancing.

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Capacity Modulation of a Multi-Type Heat Pump System Using PID Control (PID 제어를 이용한 멀티형 열펌프의 용량조절)

  • 정대성;김민성;김민수;이원용
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.5
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    • pp.446-475
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    • 2000
  • Performance of a water-to-water multi-type heat pump system using R22 has been experimentally investigated. Total refrigerant flow rate was adjusted with a variable speed compressor and the refrigerant flow rate for two indoor units were controlled by electronic expansion valves. Evaporator outlet pressure of refrigerant and indoor unit outlet temperatures of secondary fluid were selected as controlled variables. Experiments were carried out for both cooling and heating modes using PID control method. Results show that the multi-type heat pump system can be adequately controlled by keeping control gains at certain levels for various operating conditions.

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Design of Neuro-Fuzzy Controller using Relative Gain Matrix (상대이득행렬을 이용한 뉴로 퍼지 제어기의 설계)

  • 서삼준;김동식
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.157-157
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    • 2000
  • In the fuzzy control for the multi-variable system, it is difficult to obtain the fuzzy rule. Therefore, the parallel structure of the independent single input-single output fuzzy controller using a pairing between the input and output variable is applied to the multi-variable system. The concept of relative gain matrix is used to obtain the input-output pairs. However, among the input/output variables which are not paired the interactive effects should be taken into account. these mutual coupling of variables affect the control performance. Therefore, for the control system with a strong coupling property, the control performance is sometimes lowered. In this paper, the effect of mutual coupling of variables is considered by tile introduction of a simple compensator. This compensator adjusts the degree of coupling between variables using a neural network. In this proposed neuro-fuzzy controller, the Neural network which is realized by back-propagation algorithm, adjusts the mutual coupling weight between variables.

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