• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.48-53
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• 1989

We attempt to achieve both high dynamic performance and maximal power efficiency by means of linear decoupling of rotor speed (or motor torque) and rotor flux. The induction motor with our controller possesses the input-output dynamic characteristics of a linear system such that the rotor speed (or motor torque) and the rotor flux are decoupled. The rotor speed (or motor torque) responses are not affected by abrupt changes in the rotor flux and vice versa. The rotor flux need not be measured but is estimated by the well-known flux simulator. The effect of large variation in the rotor resistance on the control performances is minimized by employing a parameter adaptation method. To illuminate the significance of our work. we present simulation and experimental results as well as mathematical performance analyses.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.7
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• pp.17-23
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• 2013

The regulation of currents in a three-phase load is an important issue for electric power systems. The most popular conventional method is a decoupling controller that compensates the coupling terms arising from DQ rotating frame transformation. Although the decoupling controller achieves decent performance in the absence of load parameter uncertainties, the variation of parameters causes performance to degrade intolerably. In this paper, we propose to use disturbance observer based controller to improve the control performance in spite of the parameter uncertainties. The computer simulation study validates the effectiveness of the proposed method.

• 전기의세계
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• v.23 no.2
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• pp.46-54
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• 1974

The purposes of this paper are to deal with the design of m-input, m-output linear systems by the state variable feedback, and to extend the design capability of the state variable feedback design. The design requirements are decoupling and the exact realigation of desired transfer functions. Some methods are proposed to insert series compensators in the fixed plant in the cases when series compensators are needed to meet the input-output transfer matrix specification. The method for adding series compensators to the input channels of the fixed plant is shown by examples to lead both to the loss of the ability to decouple the augmented plant by the state variable feedback, and to the loss of desired zeroes. A method which avoids these two hazards is developed in which series compensators are put on the output channels of the fixed plant: it is proved that the augmented plant is F-invariant. By treating each subsystem individually, the designer can apply some of the previous developed knowledge of the state variable design of single-input, single-output systems.

• Membrane and Water Treatment
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• v.9 no.2
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• pp.129-136
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• 2018

In this contribution, the control of multivariable reverse osmosis (RO) desalination plant using proportional-integral-derivative (PID) controllers is presented. First, feed-forward compensators are designed using simplified decoupling method and then the PID controllers are tuned for flux (flow-rate) and conductivity (salinity). The tuning of PID controllers is accomplished by minimization of the integral of squared error (ISE). The ISEs are minimized using a recently proposed algorithm named as teacher-learner-based-optimization (TLBO). TLBO algorithm is used due to being simple and being free from algorithm-specific parameters. A comparative analysis is carried out to prove the supremacy of TLBO algorithm over other state-of-art algorithms like particle swarm optimization (PSO), artificial bee colony (ABC) and differential evolution (DE). The simulation results and comparisons show that the purposed method performs better in terms of performance and can successfully be applied for tuning of PID controllers for RO desalination plants.

• Journal of Mechanical Science and Technology
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• v.19 no.3
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• pp.731-742
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• 2005

A magnetic bearing even with multiple coil failure can produce the same decoupled magnetic forces as those before failure if the remaining coil currents are properly redistributed. This fault-tolerant, force invariance control can be achieved with simply replacing the distribution matrix with the appropriate one shortly after coils fail, without modifying feedback control law. The distribution gain matrix that satisfies the necessary constraint conditions of decoupling linearized magnetic forces is determined with the Lagrange Multiplier optimization method.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.6
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• pp.403-407
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• 2018

This study proposes a predictive direct power control method in a modular multilevel converter (MMC) high-voltage direct-current (HVDC) system. The conventional proportional integral (PI)-based control method uses a cascaded connection and requires an optimal gain selection procedure and additional decoupling scheme. However, the proposed control method has a simple structure for active/reactive power control due to the direct power control scheme and exhibits a fast dynamic response by predicting the future status of system variables and considering time delay. The effectiveness of the proposed method is verified by simulation results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.2
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• pp.142-145
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• 2018

In this paper, we present a design technique for the suppression of common-mode(CM) noise in switched-mode power supply boards using the segmentation method. By applying the segmentation method, the example structure is decomposed into two segments with decoupling capacitors and a recombination matrix is extracted for the segments. The effects of the decoupling capacitor on CM noise suppression are examined. The simulation time is significantly reduced on using the segmentation method.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.315-317
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• 2000

Linear induction motor(LIM) have static and dynamic end effects due to its finite core length, so that per-phase impedances are asymmetric and the air gap flux distribution is distorted. So, this paper propose the d-q axis equivalent circuit and vector control method considering both static and dynamic end effects of the LIM. This vector control method consists of the slip frequency control, the time-invariant control and decoupling control. As a result, it is shown that the results of equivalent circuit method have a goof agreement with the results of finite element method.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.66-68
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• 2018

6상 전동기는 높은 신뢰성과 토크 리플의 저감 등의 성능 이점으로 인해 다양한 산업 분야에서 고려되고 있다. 6상 전동기는 일반적으로 두 3상 권선의 형태로 모델링할 수 있으며, 독립된 두 개의 전류 제어기를 사용하는 경우, 두 3상 권선 간의 상호 간섭 인덕턴스의 영향으로 인하여 불안정해지는 특성이 있다. 안정적인 전동기 구동을 위하여, 비대칭 6상 전동기의 상호 간섭 영향을 최소화하는 전류 제어기가 필요하다. 이를 위해, 본 연구에서는 이산 영역에서의 6상 전동기의 전류 제어 폐루프 응답 특성을 분석하고 비간섭 (Decoupling) 전류 제어기 구조를 제시한다.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.39-39
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• 2000

In this paper, a decoupler of tandem cold rolling mill is designed. Before designing the decoupler, this paper improved conventional linear model by considering friction and yield stress of rolling strip. In a stand, the decoupler let an output be controlled by an input. And even if states of other stands should be changed, current stand takes no interference from those changes. In addition, with the same method, a feedforward controller is designed for an input strip thickness error. Finally, performance of controllers above is shown with nonlinear simulation.