• 조명전기설비학회논문지
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• 제13권4호
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• pp.27-31
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• 1999

본 연구는 산업분야의 수많은 전기설비 시스템에 널리 사용되고 있으며 또 이중여자기로도 사용될 수 있는 권선형 유도전동기의 기동특성과 설계를 다루었다. 고정자는 재래색 3상 권선형 유도 전동기의 고정자와 동일하고 회전자 권선은 새로운 방법으로 재권선한 결과 기동토크로 크고 기동전류는 작으며 운전효율은 좋아졌다. 뿐만 아니라 슬립링과 브러쉬 및 외부저항의 필요성이 없어 구조가 간단하고 시스템 비용을 절약할 수 있을 뿐 아니라 유지보수비도 절약할 수 있었다.

• 대한전기학회논문지
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• 제40권12호
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• pp.1218-1229
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• 1991

The time optimal position control design can be repeatedly taken from the initial state of a dynamic system to a desired one as fast as possible in the industrial drives. In this case, an induction machine parameters will vary due to temperature, frequency, and saturation effects. In particular, the rotor resistance changes critically 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 ones of the induction motor drive, and this situation leads to coupling of the vector controller from the plant, i.e. the induction motor . Consequences of such a coupling include the initiation of oscillations of the rotor flux and unsuitable switching of electromagnetic torque for the induction motor servo drive. Therefore, this paper describes a rotor resistance parameter compensating method for the induction motor, And the validity of the proposed design method is confirmed by simulation studies and experiment results.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권3호
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• pp.154-161
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• 2005

This paper proposes a speed-sensorless induction motor control system using a rotor speed compensation. To explain the proposed system, this paper describes an induction motor model in the synchronous reference frame for the vector control. The rotor flux is estimated by the rotor flux observer using the reduced-dimensional state estimator technique. The estimated rotor speed is directly obtained from the electrical frequency, the slip frequency, and the rotor speed compensation with the estimated q-axis rotor flux. The error of the rotor time constant is indirectly reflected in the rotor speed compensation using the compensation of the flux error angle. To precisely estimate the rotor flux, the actual value of the stator resistance, whose actual variation is reflected, is derived. An implementation of pulse-width modulation (PWM) pulses using an effective space vector modulation (SVM) is briefly mentioned. For fast calculation and improved performance of the proposed algorithm, all control functions are implemented in software using a digital signal processor (DSP) with its environmental circuits. Also, it is shown through experimental results that the proposed system gives good performance for the speed-sensorless induction motor control.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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• pp.27-29
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• 1999

The starting characteristics of induction motors strongly depend on the leakage reactance and resistance of stator winding and rotor circuits. The magnetic field saturation in the rotor bridge of closed slot rotor makes it very difficult to compute the leakage reactance of rotor bars. This paper describes a comparison between timestep finite element analysis, time-harmonic analysis and experimental results for a test model which can represent the nonlinear behaviour of the rotor bridge.

• 대한전기학회논문지
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• 제38권11호
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• pp.877-887
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• 1989

In this paper, we attempt to achieve high dynamic performance by means of decoupled control of rotor speed and flux. Recently developed nonlinear feedback control theories are utilized. The rotor fluxes are estimated based on the rotor circuit equations. When the estimation error of the rotor flux tends to zero, the rotor speed and flux dynamic characteristics of the induction motor with our controller become linear. To minimize the deterioration of control performance, we use an identification algorithm for the rotor resistance. We analyze the dynamic behavior of the closed loop system with our controller. Both simulation and experimental results are included to demonstrate the practical significance of our result. In particular, our experimental results show that recently developed nonlinear feedback control techniques are of practical use in control of induction motors.

• 대한기계학회논문집B
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• 제26권2호
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• pp.184-193
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• 2002

This study aims at the optimal design of the screw rotor and its performance analysis. The optimal design of the screw rotor's shape has been performed theoretically. Also, the performance analysis technique of an oil-injected screw air compressor is developed. The effect of internal leakage, heat exchange between air and oil, and flow resistance at suction and discharge ports are included in the performance analysis. Some numerical examples of the volumetric efficiency and adiabatic efficiency for sample rotors are demonstrated for various lobe combination, rotor wrap angles and L/D ratios.

• 한국자기학회지
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• 제26권2호
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• pp.67-69
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• 2016

최근 중국의 희토류 자석 생산 독점과 수출 규제로 인해 희토류 자석의 가격이 급등하였다. 이러한 경제적인 문제로 인해, 희토류 자석을 사용하지 않는 유도전동기의 연구가 활발히 이루어지고 있다. 이 논문에서는 유도전동기의 토크를 계산하고, 농형 유도전동기의 회전자 단면적과 저항에 관한 상관관계를 연구하였다. 또한, 회전자의 단면적이 같고 형상이 다를 경우, 회전자의 누설 리액턴스와 토크의 상관관계에 대해 분석하여 농형 유도전동기를 개선하고자 하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.193-193
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• 2003

• 조명전기설비학회논문지
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• 제25권4호
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• pp.45-56
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• 2011

This paper is proposed artificial neural network(ANN) rotor resistance estimation of induction motor drive controlled by multi-adaptive fuzzy learning controller(AFLC). A simple double layer feedforward ANN trained by the back-propagation technique is employed in the rotor resistance identification. In this estimator, double models of the state variable estimations are used; one provides the actual induction motor output states and the other gives the ANN model output states. The total error between the desired and actual state variables is then back propagated to adjust the weights of the ANN model, so that the output of this model tracks the actual output. When the training is completed, the weights of the ANN correspond to the parameters in the actual motor. The estimation and control performance of ANN and multi-AFLC is evaluated by analysis for various operating conditions. Also, this paper is proposed the analysis results to verify the effectiveness of this controller.