• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.181-186
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• 2006

본 논문에서는 자속 궤환을 포함하는 자기부상 시스템의 open-loop 특성에 대해서 다룬다. 훌륭한 외란 억제 특성을 포함하고 파라메타 변동에 대해서 둔감한 제어기를 설계하기 위해서 자속 궤환을 이용하는 것이 효과적일 수 있다. 적절한 센서에 의해서 측정 가능한 자속은 전류와 공극의 시간 변화에 대해서 선형적인 관계를 가지고 있으며, 자속의 궤한은 자기 부상시스템이 본질적으로 갖고 있는 전기적 엑츄에이터와 기계적 플랜트 사이의 간섭에 의해서 발생하는 비선형성을 감소시키는 역할을 한다. 모의시험 결과를 통해서 자속의 궤환이 자기부상 시스템의 부하변동에 대해서 open-loop 성능 향상에 효과적임을 보인다.

• Journal of the Korean Society for Railway
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• v.9 no.4 s.35
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• pp.455-460
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• 2006

본 논문에서는 자속 궤환을 포함하는 자기부상 시스템의 open-loop 특성에 대해서 다룬다. 훌륭한 외란 억제 특성을 포함하고 파라메타 변동에 대해서 둔감한 제어기를 설계하기 위해서 자속 궤환을 이용하는 것이 효과적일 수 있다. 적절한 센서에 의해서 측정 가능한 자속은 전류와 공극의 시간 변화에 대해서 선형적인 관계를 가지고 있으며, 자속의 궤한은 자기 부상시스템이 본질적으로 갖고 있는 전기적 엑츄에이터와 기계적 플랜트 사이의 간섭에 의해서 발생하는 비선형성을 감소시키는 역할을 한다. 모의시험 결과를 통해서 자속의 궤환이 자기부상 시스템의 부하변동에 대해서 Open-loop 성능 향상에 효과적임을 보인다.

• Journal of the Korean Magnetics Society
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• v.22 no.1
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• pp.23-26
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• 2012

New digital feedback algorithm was developed to measure iron loss of soft magnetic materials under a condition of sinusoidal flux waveform. $V_{in}$(B) curve was used instead of H(B) curve to decide next input waveform in the feedback module so that adjusting phases of current waveform, flux waveform, and input waveform could be removed. The effectiveness of the developed algorithm was verified when iron loss of ferrite cores was measured under frequencies of 1 and 10 kHz.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.136-147
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• 1993

The paper describes : ⅰ) Mathematical modeling of poloidal flux to define and calculate the tokamak plasma position based on a property of the plasma boundary which is always a flux surface. Controlling the plasma boundary position is therefore equivalent to equalizing the flux value on several points belonging to a curve tangent to the limiter. ⅱ) Experimental method for determining the outmost poloidal isoflux surface by a linear combination of measurements of magnetic fluxes, fields and field gradients, without requiring knowledge of internal plasma parameters for the feedback control, i.e., with neither corrections for variation in the poloidal beta and the plasma current distribution, nor compensations for the induced currents in the vacuum vessel. ⅲ) Feedback control algorithm for the regulation of plasma boundary position and its electronics hardware based on the PID control theory. ⅳ) Experimental results obtained from the RTP tokamak experiments using the present plasma control system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.3 s.108
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• pp.283-290
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• 2006

This study is concerned with static and sinusoidal disturbance rejection for a single periodic input disturbance with known period. In the area of active elimination of a disturbance force, the control input should have two different kinds of gains: one is to deliver a stable control and the other is a force component to cancel the external disturbance force. In this paper we employ a simple state feedback control law to make the balance beam stable and employ a linear observer to estimate the states which represent the external disturbance force components. Simulation results verify our proposed control method to reject a static and sinusoidal disturbance force.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.3
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• pp.99-103
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• 1998

We propose a nonlinear feedback controller that can control the induction motors which have been applied to many electrical facilities with high dynamic performance by means of decoupling of moor speed and rotor flux. The nonlinear feedback controller needs the information on some motor parameters. Among them, rotor resistance varies greatly with machine temperature. Anew recursive adaptation algorithm for rotor resistance which can e applied to our nonlinear feedback controller is also presented in this paper. To demonstrate the practical significance of our results, we present some experimental results.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.88-90
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• 2008

본 논문은 이중여자 유도형(DFIG) 풍력발전 시스템에서 유효전력과 무효전력을 직접적으로 제어하기 위해 가변구조제어의 일종인 스위칭 이득기반의 선형궤환(LFSG)제어기법을 제시한다. 개조된 직접전력제어기법 (DPC)과 공간벡터변조방식(SVM)은 제안하는 제어기법을 실현하기 위해 이용된다. 개조된 직접전력제어원리를 이용해서 설계된 LFSG제어기법은 널리 사용되고 있는 자속기준제어기법(FOC)에 비해서 간단한 제어구조로 강인성과 빠른 응답특성을 보인다. 시뮬레이션결과는 제안하는 제어전략의 타당성과 강인성을 확인해준다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.4
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• pp.81-89
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• 1998

In the field of industrial drives, the vector control of the induction motor has been widely used to achieve the good control performance. In this paper, to require the information of rotor flux in direct vector control scheme, the flux observer by current model of rotor circuit is used. This flux observer is not only available at low-speed region bt good for the error reduction by feedback properties. Also, employing the flux observer on rotor reference frame, the robustness of decoupling control to the observation of rotor flux can be achieved. Through digital simulation and DSP-based IGBT inverter system, the validity for practical implementation is verified.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.5 no.4
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• pp.8-14
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• 1991

In this paper, the variable speed control of permanent magnet synchronous motor driven by a sinusoidal PWM inverter based on maximun torque sensitivity is presented. The developed torque or speed control is achieved by the field orientation technique. For the field orientation, the resolver is used as the rotor positioning sensor mounted on the motor shaft without pull-out of the synchonism at any speed. To show the validity of proposed control method, the simulation and experimental results are provided. The advantages of the proposed control method are to achieve the fast current and speed responses.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.5 no.1
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• pp.46-56
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• 1991

In this paper, the variable speed control of permanent magnet synchronous motor driven by a sinus¬oidal PWM inverter based on maximum torque sensitivity is presented. The developed torque or speed control is achieved by the field orientation technique. For the field orientation, the resolver is used as the rotor positioning sensor mounted on the motor shaft without pull-out of the synchonism at any speed. To show the validity of proposed control method, the simulation and experimental results are provided. The advantages of the proposed control method are to achieve the fast current and speed responses.