• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.391-393
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• 2007

The rotor speed and flux information is most important in the vector control. The accuracy of flux observers for induction machine inherently depends on parameter sensitivity. The control strategy is using online flux observer for flux estimation. In the proposed system, the speed control characteristics using a online flux observer control isn't affected by a load torque parameter disturbance. Simulation results are presented to prove the effectiveness of the adaptive sliding mode controller for the drive variable load of induction motor.

• International Journal of Control, Automation, and Systems
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• 제4권4호
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• pp.414-427
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• 2006

This paper presents an adaptive feedback linearization control scheme for induction motors with simultaneous variation of rotor and stator resistances. Two typical modeling techniques, rotor flux model and stator flux model, have been developed and successfully applied to the controller design and adaptive observer design, respectively. By using stator fluxes as states, over-parametrization in adaptive control can be prevented and control strategy can be developed without the need of nonlinear transformation. It also decrease the relative degree for the flux modulus by one, thereby, yielding, a simple control algorithm. However, when this method is used for flux observer, it cannot guarantee the convergence of flux. Similarly, the rotor flux model may be appropriate for observers, but it is not so for adaptive controllers. In addition, if these two existing methods are merged into overall adaptive control system, it brings about structural complexies. In this paper, we did not use these two modeling methods, and opted for the airgap flux model which takes on only the positive aspects of the existing rotor flux model and stator flux model and prevents structural complexity from occuring. Through theoretical analysis by using Lyapunov's direct method, simulations, and actual experiments, it is shown that stator and rotor resistances converge to their actual values, flux is well estimated, and torque and flux are controlled independently with the measurements of rotor speed, stator currents, and stator voltages. These results were achieved under the persistent excitation condition, which is shown to hold in the simulation.

• 한국조명전기설비학회지:조명전기설비
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• 제10권3호
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• pp.55-63
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• 1996

본 논문에서는 CRPWM 인버터로 구동되는 유동전동기의 벡터젝어를 구현하였다. 회전자자속은 회전자 좌표계 자속모델을 이용하여 추정하였으며 전류제어기는 고정좌표계 삼각파 비교 제어기를 사용하였다. 회전자자속의 추정, 속도제어기, 자속제어기, 벡터회전, 상 변화 등의 연산은 80C196 마이크로 콘트롤러를 사용하여 실시간 제어를 하였으며 전류 제어기는 마이크로 콘트롤러의 처리부담을 덜어주기 위해 아날로그회로로 구현하였다. 제안한 시스템에 대하여 시뮬레이션을 통하여 타당성을 검토하였으며 실험을 통하여 전류제어 특성과 시스템의 과도 응답 특성이 우수함을 보였다.

• 전력전자학회논문지
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• 제8권5호
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• pp.375-380
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• 2003

기존의 속도센서가 없는 유도전동기의 고정자자속 기준제어에서 추정된 속도가 이산화 될 때, 이산화에 의한 모델링오차 때문에 회전자속도 추정에 오차가 발생한다. 이 오차는 저역통과필터에 의해 제거되지만 추정된 속도는 과도상태에서 지연이 발생해서 약계자영역으로의 천이가 지연되는 문제가 발생하게 된다. 본 논문에서는 기존의 고정자자속 기준제어 속도 센서리스 시스템의 약계자영역에서 추정된 속도의 지연으로 발생하는 문제점을 고찰하고 또한 루엔버거관측기를 사용하여 정확한 속도 추정을 학 수 있는 방법을 제안한다.

• Journal of Electrical Engineering and Technology
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• 제2권4호
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• pp.468-477
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• 2007

The DTC of voltage source inverter-fed PMSMs is based on hysteresis controllers of torque and flux. It has several advantages, namely, elimination of the mandatory rotor position sensor, less computation time, and rapid torque response. In addition, the stator resistance is the only parameter, which should be known, and no reference frame transformation is required. The DTC theory has achieved great success in the control of induction motors. However, for the control of PMSM drives proposed a few years ago, there are many basic theoretical problems that must be clarified. This paper describes an investigation into the effect of the zero voltage space vectors in the DTC system and points out that if using it rationally, not only can the DTC of the PMSM drive be driven successfully, but torque and flux ripples are reduced and overall performance of the system is improved. The implementation of DTC in PMSM drives is described and the switching tables specific for an interior PMSM are derived. The conventional eight voltage-vector switching table, which is namely used in the DTC of induction motors does not seem to regulate the torque and stator flux in a PMSM well when the motor operates at low speed. Modelling and simulation studies have both revealed that a six voltage-vector switching table is more appropriate for PMSM drives at low speed. In addition, the sources of difficulties, namely, the error in the detection of the initial rotor position, the variation of stator resistance, and the offsets in measurements are analysed and discussed.

• 한국항행학회논문지
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• 제16권6호
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• pp.1005-1013
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• 2012

본 논문에서는 $1/{\tau}$에 영향을 받는 간접 벡터 제어 방법으로 유도 전동기의 간접 벡터제어 방법을 모델링하였으며, 회전자 저항의 변화에 따른 자속 및 회전각을 추정하고 이것과 관계있는 속도 추정과 파라미터의 변하에 따른 것들을 Matlab/Simulink를 통하여 시뮬레이션하였다. 제안한 제어시스템의 고속 연산처리를 위하여 마이크로프로세서는 실시간 제어가 가능한 TMS320C31 DSP를 이용하였고, 속도제어 구동시스템의 성능을 알아보기 위해 컴퓨터 시뮬레이션을 통하여 그 타당성을 검토하였으며, 실험을 통해 컴퓨터 시뮬레이션 결과와 일치함을 보였다. 결과에서 보듯이 빠른 속도추정 특성과 부하변동에 대해서도 강인한 특성을 갖고 있음을 확인하였다. 이와 같은 상태를 시뮬레이션을 하였고 그 결과를 분석을 하여 좋은 시뮬레이션 결론을 얻을 수 있었다.

• Journal of Power Electronics
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• 제13권2호
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• pp.264-274
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• 2013

A new sensorless position estimation method for switched reluctance motor (SRM) drives is presented in this paper. This method uses the change of the slope of the phase inductance to detect the aligned position. Since the aligned positions for successive electrical cycle of each phase are apart by a fixed mechanical angle $45^{\circ}$ in the case of 12/8 SRM, the speed of the machine can be calculated to estimate the rotor position. Since no prior knowledge of motor parameters is required, the method is easy for implementation without adding any additional hardware or memory. In order to verify the validity of this technique, effects such as changes in the advanced angle and phase lacking faults are examined. In addition, an inductance threshold based sensorless starting scheme is also proposed. Experimental results demonstrate the validity of the proposed method.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.100-109
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• 2017

This paper proposes performance improvement schemes for sensorless PMSM control drive using a four-switch three-phase inverter (so-called B4 inverter). In the proposed scheme, the back-EMF estimation-based sensorless control algorithm is used to control the brushless PMSM without position sensors. In order to have stable operation, this paper presents a gain adjustment scheme that compensates the reduction of stable sensorless operation range as long as the rotor speed increases. In B4 topology, the center point of dc-link capacitors is connected to 3-phase load, and it is prone to have the load current distortion. Hence, to mitigate this problem, a distortion compensation scheme by modifying voltage commands using measured dc-link potentials is proposed in this paper. The validity of the proposed method is evaluated by simulations and experiments.

• ETRI Journal
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• 제37권6호
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• pp.1154-1164
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• 2015

This paper proposes a fully sensorless driver for a permanent magnet synchronous motor (PMSM) integrated with a digital motor controller and an analog pre-driver, including sensing circuits and estimators. In the motor controller, a position estimator estimates the back electromotive force and rotor position using a sliding-mode observer. In the pre-driver, drivers for the power devices are designed with a level shifter and isolation technique. In addition, a current sensing circuit measures a three-phase current. All of these circuits are integrated in a single chip such that the driver achieves control of the speed with high accuracy. Using an IC fabricated using a $0.18{\mu}m$ BCDMOS process, the performance was verified experimentally. The driver showed stable operation in spite of the variation in speed and load, a similar efficiency near 1% compared to a commercial driver, a low speed error of about 0.1%, and therefore good performance for the PMSM drive.

• 전력전자학회논문지
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• 제10권2호
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• pp.186-193
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• 2005

본 논문에서는 산업체 CNC(Computer Numerical Control) 분야에서 사용되는 빌트인 타입 스핀들 모터를 구동하기 위한 기법을 제시하였다. 저속 영역에서 유리한 전류 모델과 고속 영역에서 유리한 전압 모델을 혼합해서 사용하는 고피나스 모델 자속추정기는 회전자 자속추정을 위하여 이용하였다. 그리고 약계자 제어를 사용하여 스핀들 모터를 고속 운전하였다. 시뮬레이션과 실험을 통해 약계자 영역에서의 스핀들 모터 고속운전을 확인하였다.