• Journal of Power Electronics
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• 제11권2호
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• pp.120-131
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• 2011

This paper proposes two control strategies for the bidirectional Z-source inverters (BZSI) supplied by batteries for electric vehicle applications. The first control strategy utilizes the indirect field-oriented control (IFOC) method to control the induction motor speed. The proposed speed control strategy is able to control the motor speed from zero to the rated speed with the rated load torque in both motoring and regenerative braking modes. The IFOC is based on PWM voltage modulation with voltage decoupling compensation to insert the shoot-through state into the switching signals using the simple boost shoot-through control method. The parameters of the four PI controllers in the IFOC technique are designed based on the required dynamic specifications. The second control strategy uses a proportional plus resonance (PR) controller in the synchronous reference frame to control the AC current for connecting the BZSI to the grid during the battery charging/discharging mode. In both control strategies, a dual loop controller is proposed to control the capacitor voltage of the BZSI. This controller is designed based on a small signal model of the BZSI using a bode diagram. MATLAB simulations and experimental results verify the validity of the proposed control strategies during motoring, regenerative braking and grid connection operations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1729_1730
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• 2009

This paper presents comparative experimental results of PI sliding mode control and PI control for a heavy duty robot which can handle an object of 600kg, The gains of the PI control was determined by TAE(Trial and Error) method. This paper presents a novel approach for the decoupling of the states cross-coupling using sliding mode control. The sliding mode control methode is based on the error between reference speeds and the actual speed. The proposed method has the advantages of PI control performance and the sliding mode control robustness. Its first step is to design PI controller, then the sliding mode control input term is added to it. This makes actual implementation of the controller easier. The robot and motion controllers were designed and made by author. The good control performance of the heavy duty robot was obtained by using simple algorithm. This means that the robot was designed very well in control respect.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.20-24
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• 1989

The time optimal position control scheme can be repeatedly taken from the initial state of a dynamic system to a desired one as fast as possible at the industrial drives. In this case, the machine parameters will vary due to temperature, frequency, and saturation effects. In particular, the rotor resistance value changes dramatically with temperature and frequency. These changes affect the command values of the stator current components and slip speed. There is a mismatch between the commanded variables and actual variables of the induction motor drive, and this situation leads to decoupling of the vector controller from the plant, i.e the induction motor. Consequences of such decoupling include the initiation of oscillations of the rotor flux and unsuitable switching of electromagnetic torque of the induction motor servo drive. Therefore, a rotor resistance parameter compensating method for the induction motor is described.

• 한국결정학회지
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• 제14권1호
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• pp.35-38
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• 2003

증기-확산 단백질 결정화의 물-증발 속도를 조절하기 위해서, 간결한 모세관 내의 다중-단계 농도 장착법 (multistep-concentration setting in capillaries) 이 이용되었다. “조절 용액 (regulatory solution)”이라고 일컬어지는 2차 침전 용액이 이용되어, 이 방법으로 다양한 증발 속도 곡선들이 얻어졌다. 이때, 조절 용액은 단백질 용액에 직접적으로 노출되지 않는다. 모델 단백질인 lysozyme의 결정화에 이 그래프들이 적용되었다. 결정 성장은 증발속도에 달려있다는 것을 실험 결과들이 명백하게 보여주었다. 특히나. 단백질 용액의 침전 농도가 어떤 점까지 증가하다가 평형 농도로 줄어드는 decoupling 곡선이 가장 좋은 결정들을 만들어냈다.

• 전력전자학회논문지
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• 제11권5호
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• pp.404-408
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• 2006

본 논문에서는 복소 벡터 동기 좌표계 비례 적분(PI) 전류 제어기의 안티 와인드업(anti-windup)이득 설정에 대해 논의한다. 복소 벡터 동기 좌표계 비례 적분 전류 제어기는 시스템 제정수 변동에 기존의 비례 적분 전류 제어기 보다 더 강인한 특성을 보인다. 복소 벡터 전류 제어기 역시 적분기를 포함하고 있으며, 엑츄에이터(actuator)의 물리적인 한계로 전압이 포화되는 경우에는 안티 와인드업이 필요하게 되고, 적절치 못한 안티 와인드업 이득 설정은 제어 시스템의 동특성을 저하시킬 수 있다. 따라서 복소 벡터 동기 좌표계 비례 적분 전류 제어기에 적합한 안티 와인드업 이득을 제안하였고, 제안된 알고리즘의 유효성은 실험을 통하여 검증하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.598-603
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• 2005

In this study, an adaptive control scheme with a pre-specified $H_{\infty}$ property is proposed for the tracking control of linear induction motor (LIM) drive system. Under the influence of uncertainties and external disturbances, by using nonlinear decoupling and parameter tuner, the robust performance control problem is formulated as a nonlinear $H_{\infty}$ problem and solved by a quadratic storage function. This new design method is able to track the step and several periodic commands with improved performance in face of parameter perturbations and external disturbances. Simulation and experimental results are provided to demonstrate the effectiveness of the proposed adaptive $H_{\infty}$ controller.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.846-851
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• 2004

In this paper, a sliding mode control based on disturbance observer is proposed to attenuate disturbance responses in an active magnetic bearing system, which is subject to base motion. An algorithm for exactly decoupling the disturbance estimation dynamics from the sliding mode dynamics is developed. It is also shown that the proposed method preserves the robustness of the sliding mode and asymtotically achieves zero regulation error, in the presence of external disturbances and parametric uncertainties. The proposed control is applied to a 2-DOF active magnetic bearing system subject to base motion. The feasibility of the proposed technique is illustrated, and the results of an experimental demonstration are shown.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.407-409
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• 1998

In order to improve the tracking performance of $2{\times}2$ multivariable control systems, a fuzzy control algorithm with feedforward compensator is represented. The method consists in two steps. First, neglecting interconnections. one designs a fuzzy controller to each individual loop. In the second stage, low-order transfer functions of outputs to reference inputs are estimated. We propose a design method of the feed forward compensator based on the transfer functions. An illustrative example are shown.

• 전력전자학회논문지
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• 제11권5호
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• pp.426-430
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• 2006

본 논문에서는 제어 시지연을 갖는 고성능 PI 전류제어기에 대한 새로운 예측전류 적용방법을 모색한다. 먼저 선형 영구자석 동기전동기를 사용한 선형 서보 제어시스템에 존재하는 불가피한 전류예측 오차원인을 분석하고, 전류예측 오차와 제어 시지연을 고려한 전류제어 성능 개선 방법으로 수정된 동기좌표계 비간섭 PI 전류제어기를 제안한다. 그리고 시뮬레이션 및 실험 결과를 통하여 제안된 전류제어기가 서보 제어시스템에 존재하는 전류예측 오차와 제어 시지연이 있는 경우에도 개선된 전류제어응답을 보임을 검증하였다.

• International Journal of Control, Automation, and Systems
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• 제6권5호
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• pp.677-688
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• 2008

In this paper, the general problem of impedance control for a robotic manipulator with a moving flexible base is addressed. Impedance control imposes a relation between force and displacement at the contact point with the environment. The concept of impedance control of flexible base mobile manipulator is rather new and is being considered for first time using singular perturbation and new sliding mode control methods by authors. Initially slow and fast dynamics of robot are decoupled using singular perturbation method. Slow dynamics represents the dynamics of the manipulator with rigid base. Fast dynamics is the equivalent effect of the flexibility in the base. Then, using sliding mode control method, an impedance control law is derived for the slow dynamics. The asymptotic stability of the overall system is guaranteed using a combined control law comprising the impedance control law and a feedback control law for the fast dynamics. As first time, base flexibility was analyzed accurately in this paper for flexible base moving manipulator (FBMM). General dynamic decoupling, whole system stability guarantee and new composed robust control method were proposed. This proposed Sliding Mode Impedance Control Method (SMIC) was simulated for two FBMM models. First model is a simple FBMM composed of a 2 DOFs planar manipulator and a single DOF moving base with flexibility in between. Second FBMM model is a complete advanced 10 DOF FBMM composed of a 4 DOF manipulator and a 6 DOF moving base with flexibility. This controller provides desired position/force control accurately with satisfactory damped vibrations especially at the point of contact. This is the first time that SMIC was addressed for FBMM.