• Journal of Power Electronics
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• 제7권2호
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• pp.159-173
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• 2007

In this paper, an intelligent sliding-mode position controller (ISMC) for achieving favorable decoupling control and high precision position tracking performance of permanent-magnet synchronous motor (PMSM) servo drives is proposed. The intelligent position controller consists of a sliding-mode position controller (SMC) in the position feed-back loop in addition to an on-line trained fuzzy-neural-network model-following controller (FNNMFC) in the feedforward loop. The intelligent position controller combines the merits of the SMC with robust characteristics and the FNNMFC with on-line learning ability for periodic command tracking of a PMSM servo drive. The theoretical analyses of the sliding-mode position controller are described with a second order switching surface (PID) which is insensitive to parameter uncertainties and external load disturbances. To realize high dynamic performance in disturbance rejection and tracking characteristics, an on-line trained FNNMFC is proposed. The connective weights and membership functions of the FNNMFC are trained on-line according to the model-following error between the outputs of the reference model and the PMSM servo drive system. The FNNMFC generates an adaptive control signal which is added to the SMC output to attain robust model-following characteristics under different operating conditions regardless of parameter uncertainties and load disturbances. A computer simulation is developed to demonstrate the effectiveness of the proposed intelligent sliding mode position controller. The results confirm that the proposed ISMC grants robust performance and precise response to the reference model regardless of load disturbances and PMSM parameter uncertainties.

• 한국정밀공학회지
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• 제25권6호
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• pp.134-142
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• 2008

In this paper, we propose a precise linear motion stage supported by magnetically preloaded air bearings. The eight aerostatic bearings with rectangular carbon porous pads were located only one side of vertical direction under the platen where four bearings are in both sides of horizontal direction as wrap-around-design, and this gives simpler configuration than which constrained by air bearings for all direction. Each of the magnetic actuators has a permanent magnet generating static magnetic flux far required preload and a coil to perturb the magnetic farce resulting adjustment of air- bearing clearance. The characteristics of porous aerostatic bearing are analyzed by numerical analysis, and analytic magnetic circuit model is driven for magnetic actuator to calculate preload and variation of force due to current. A 1-axis linear stage motorized with a coreless linear motor and a linear encoder was designed and built to verify this design concept. The load capacity, stiffness and preload force were examined and compared with analysis. With the active magnetic preloading actuators controlled with DSP board and PWM power amplifiers, the active on-line adjusting tests about the vertical, pitching and rolling motion were performed. It was shown that motion control far three DOF motions were linear and independent after calibration of the control gains.

• Journal of Power Electronics
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• 제17권6호
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• pp.1500-1511
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• 2017

The purpose of this paper is to study a high-performance control scheme for neutral-point-clamping three-level (NPC-3L) inverter fed dual three-phase permanent magnet synchronous motor (PMSM) drives by considering some asymmetric factors such as the non-identical parameters in phase windings. To implement this, the system model is analyzed for dual three-phase PMSM drives with asymmetric factors based on the vector space decomposition (VSD) principle. Based on the equivalent circuits, PI controllers with feedforward compensation are used in the d-q subspace for regulating torque, where the cut-off frequency of the PI controllers are set at the twice the fundamental frequency for compensating both the additional DC component and the second order component caused by asymmetry. Meanwhile, proportional resonant (PR) controllers are proposed in the x-y subspace for suppressing the possible unbalanced currents in the phase windings. A dual three-phase space vector modulation (DT-SVM) is designed for the drive, and the balancing factor is designed based on the numerical fitting surface for balancing the DC link capacitor voltages. Experimental results are given to demonstrate the validity of the theoretical analysis and the proposed control scheme.

• 전기전자학회논문지
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• 제22권4호
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• pp.1031-1035
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• 2018

본 논문은 저속 운전을 포함한 영구자속의 자속 추정을 통하여 Permanent Magnet Synchronous Motor(PMSM)의 토크 오차를 보상하는 기법에 대해 기술한다. 영구자속의 자속은 온도에 따라 변화한다. 동손을 최소화하기 위해 적용되는 Maximum Torque per Ampere (MTPA)는 영구자속의 자속 추정값을 이용하여 구현되기 때문에 영구자석의 자속이 변화할 경우, 토크 오차가 발생한다. 본 논문에서는 쇄교자속관측기를 이용하여 영구자석의 자속을 실시간으로 추정하여 제어알고리즘에 적용함으로써 토크 오차를 보상하는 기법을 제안한다. 제안된 기법은 시뮬레이션과 실험을 통하여 검증하였다.

• 전력전자학회논문지
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• 제24권2호
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• pp.71-77
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• 2019

This study proposes a circulating current reduction method that uses high-frequency voltage compensation when carrier phase difference occurs between two inverters in MSIS. In MSIS, inverters are configured in parallel to increase power capacity and to increase efficiency by using inverters only as needed. However, in the parallel inverter structure, circulating current is inevitably generated. Circulating current increases the stress on the switch, adversely affects the current control performance, and renders load sharing difficult. The proposed method compensates for the output voltage reference of the slave module by using the high-frequency voltage so that the switching pattern of each module is matched even in asynchronous carriers. The validity of the proposed method is verified by simulations and experiments with 600 W IPMSM.

• Journal of Power Electronics
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• 제19권1호
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• pp.146-157
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• 2019

The inverter is an essential part of permanent magnet synchronous motor (PMSM) drive systems. The performance of an inverter is greatly influenced by its modulation strategy. Using a proper management of modulation strategies can guarantee high performance from a PMSM under various speed conditions. Switching between modulations is a pivotal technique that determines the performance of a PMSM. Most works on hybrid methods focus on two-level induction motors drive systems. In this paper, in order to improve the performance of PMSMs under various speed conditions, a hybrid method of a pulse width modulation (PWM) control scheme based on a neutral-point-clamped (NPC) three level topology was proposed. This hybrid PWM modulation comprised space vector PWM (SVPWM) and selective harmonic elimination PWM (SHEPWM). Under low speed conditions, the SVPWM is employed to cause the PMSM to start smoothly, and to obtain a rapid response from the control system. Under high speed conditions, the SHEPWM is employed to reduce the switching frequency and to eliminate particular current harmonics. Moreover, the harmonic characteristics of different modulations are analyzed to obtain a smooth transition between the SHEPWM and the SVPWM. Experimental and simulation results indicated the effectiveness of the proposed control method.

• 한국인터넷방송통신학회논문지
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• 제21권1호
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• pp.115-120
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• 2021

본 논문에서는 비례공진 전류제어기 기반의 단상 영구자석 동기전동기의 운전 알고리즘을 제안하였다. 일반적으로 단상 영구자석 동기전동기의 경우 회전자의 형상에 따른 비대칭 공극이 발생할 수 있으며, 이는 고속 운전시 소음과 진동의 원인이 된다. 따라서 본 논문에서는 제어 안정성이 뛰어난 비례공진 전류제어기를 적용한 단상 영구자석 동기전동기의 운전 알고리즘을 제안하였다. 비례공진 전류제어기법은 정상상태 오차가 없고 왜란에 대해 비교적 강인한 특성을 가지고 있으며, 복잡한 연산과정 없이 교류입력의 정상상태를 제거할 수 있다. 제안한 알고리즘의 유효성과 타당성을 실험을 통해 검증하였다.

• 한국전자통신학회논문지
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• 제17권5호
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• pp.859-866
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• 2022

능동 외란제거 제어기는 루엔버거 관측기를 이용하여 상태변수를 추정하여 제어기에서 외란을 제거하는 방식이다. 루엔버거 관측기는 정상상태에서 상수의 특징을 갖는 외란을 포함하는 비선형항을 상태변수로 정의하여 추정한다. 추정된 상태변수 값을 비례적분 제어기와 적분비례 제어기에 보상하여 개선된 속도 추종 성능을 보일 수 있다. 추정된 상태의 오차는 부하변동의 경우 1.9 [%] 이내임과 정상상태 상태 추종 오차가 영으로 수렴함을 보여 상태 추종 제어기의 외란 제거성능을 보임을 확인할 수 있다.

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.38-43
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• 2021

Permanent magnet linear synchronous motor (PMLSM) is suitable for use in cleanroom environments and have advantages such as high speed, high thrust, and high precision. If the stators are arranged in the entire moving path of the mover, there is a problem in that the installation cost increases. To solve this problem, discontinuous armature arrangement PMLSM has been proposed. In this case, the mover receives a greater detent force in the section where the stator is not arranged. When a large detent force occurs, it appears as a ripple component of the thrust during PMLSM operation. If the shape of the stator is changed to reduce the detent force, the characteristics of the back EMF are changed. Therefore, in this paper, the detent force and the harmonic components of back EMF were reduced through multi-purpose shape optimization. To this end, the FEA model was constructed and main effect analysis was performed on the major shape variables affecting each objective function. Then, the optimal shape that minimizes the objective function was derived through the response surface analysis method.

• Earthquakes and Structures
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• 제24권1호
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• pp.1-9
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• 2023

A model for calculating structure interacted mechanics is proposed. A structural interaction model and controller design based on tuned mass damping (TMD) was developed to control the induced vibration. A key point is to introduce a new analytical model to evaluate the properties of the TMD that recognizes the motion-dependent nonlinear response observed in the simulations. Aiming at the problem of increased current harmonics and low efficiency of permanent magnet synchronous motors for electric vehicles due to dead time effect, a dead time compensation method based on neural network filter and current polarity detection is proposed. Firstly, the DC components and the higher harmonic components of the motor currents are obtained by virtue of what the neural network filters and the extracted harmonic currents are adjusted to the required compensation voltages by virtue of what the neural network filters. Then, the extracted DC components are used for current polarity dead time compensation control to avert the false compensation when currents approach zero. The neural network filter method extracts the required compensation voltages from the speed component and the current polarity detection compensation method obtains the required compensation voltages by discriminating the current polarity. The combination of the two methods can more precisely compensate the dead time effect of the control system to improve the control performance. Furthermore, based on the relaxed method, the intelligent approach of stability criterion can be regulated appropriately and the artificial TMD was found to be effective in reducing cross-wind vibrations.