• 전자공학회논문지B
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• 제33B권6호
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• pp.1-11
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• 1996

The rotor flux level need be changed frequently for field weakening or power efficiency control. Motor inductances depend on rotor flux but not on machine temperature. On the other hand, rotor resistance varies greatly with the machine temperature. Motor parameters such a sinductances and rotor resistance should be known precisely in order to attain high dynamic performance of inductin motor. In this paper, efficient an dnovel identification algorithms for motor inductances and rotor resistance are presented. The rotor flux is changed. As the result, the slip frequency is varied. The identificatin algorithm for rotor resistance measures the varied slip frequency and alters the estimated rotor resistance. Then, the estimated value of rotor resistance will approach its real value. The proposed identification algorithms are computationally simple and have very small identification errors.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.394-398
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• 1999

Direct Torque Control method for an Induction Motor is presented which is quite different from field-oriented control. It carries out a precise and quick control of the stator flux and electromagnetic torque of an IM without calling for coordinate transformation, speed measurement, and stator current control. In principle, moreover, DTC operation requires only the knowledge of the stator resistance.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.644-647
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• 2003

The predictive maintenance can help to avoid the serious plant breakdowns and catastrophies. This paper deals with the fault diagnosis of the rotor of the induction motor which is widely used in the plants. In order to detect the broken bar, the Extended Kalman Filter is adopted to estimate the rotor resistance on the base of model-based method. The proposed estimation method is simulated with the aid of Matlab.

• 한국안전학회지
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• 제9권4호
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• pp.42-48
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• 1994

A rotor flux error-based approach for correcting the rotor time constant estimation used in the slip frequency calculator of indirect field oriented controller is presented in this paper. The controller was derived from the d-q induction machine model. Slip frequency gain is dependent on the machine parameter errors. And parameter errors result in rotor flux error. Thus, estimated rotor flux is compared to commanded rotor flux. The error between them is used for the estimation of rotor time constant. Simulation results which demonstrate the performance of this approach are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.54-56
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• 1997

In this paper, The considerable matters for the calculation and determination of the rated electric power of the three phase Linear Induction Motor for the propulsion of a vehicle, is treated with inverter performance with harmonics, aerodynamic drag force, running resistance, normal force.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.131-134
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• 2001

The accurate identification of the motor parameters is crucially important to achieve high dynamic performance of induction motors. In this paper, the motor parameters such as rotor resistance, stator(rotor) leakage inductance, mutual inductance are measured for torque monitoring and indirect vector control. To demonstrate the practical significance of the results, some experimental results are presented.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권4호
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• pp.350-357
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• 2005

This paper presents a mechanical sensorless vector-controlled system with parameter identification by the aid of image processor. Based on the flux observer and the model reference adaptive system method, the proposed sensorless system includes rotor speed estimation and stator resistance identification using flux errors. Since the mathematical model of this system is constructed in a synchronously rotating reference frame, a linear model is easily derived for analyzing the system stability, including motor operating state and parameter variations. Because it is difficult to identify rotor resistance simultaneously while estimating rotor speed, a low-accuracy image processor is used to measure the mechanical axis position for calculating the rotor speed at a steady-state operation. The rotor resistance is identified by the error between the estimated speed using the estimated flux and the calculated speed using the image processor. Finally, the validity of this proposed system has been proven through experimentation.

• 한국가스학회지
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• 제6권4호
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• pp.40-46
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• 2002

천연가스 수송배관은 매설환경에서의 방식 및 외부충격 등에 대비하여 배관을 보호할 목적으로 폴리에틸렌(polyethylene)으로 피복(coating)되어 있다. 국내 천연가스의 보급과 함께 배관피복 기술도 초기 사용하던 폴리에틸렌 테이프에서, 분말용착식의 1층(one-layer), 압출식의 2층 피복으로 발전되어 현재는 에폭시 층이 도입된 3층 피복 시스템을 적용한 배관들이 전국에 매설되고 있다. 그러나 강관에 적용된 폴리에틸렌 피복이 경우에 따라 장기간사용에 따른 자연균열이 발생하여 피복의 안정성에 문제를 일으키기도 하므로, 상업적인 배관 피복재들의 내구 물성의 분포를 확인하여 천연가스 수송용 배관의 신뢰성 확보에 기여하고자 하였다. 이를 위하여 선진외국에서 폴리에틸렌 배관의 내구성과 장기사용안정성 평가를 위해 오래 전부터 활용되고 있는 저속균열저항성(slow crack growth resistance: SCGR)과 배관 피복층의 산화유도시간(oxidative induction time: OIT)을 측정하여 국내 배관 피복재들의 내구성을 평가하고 이를 근거로 하여 적합한 폴리에틸렌 물성치의 목표값을 제안하였다.

• The Plant Pathology Journal
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• 제29권3호
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• pp.350-355
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• 2013

Plants protect themselves from diverse potential pathogens by induction of the immune systems such as systemic acquired resistance (SAR). Most bacterial plant pathogens thrive in the intercellular space (apoplast) of plant tissues and cause symptoms. The apoplastic leaf exudate (LE) is believed to contain nutrients to provide food resource for phytopathogenic bacteria to survive and to bring harmful phytocompounds to protect plants against bacterial pathogens. In this study, we employed the pepper-Xanthomonas axonopodis system to assess whether apoplastic fluid from LE in pepper affects the fitness of X. axonopodis during the induction of SAR. The LE was extracted from pepper leaves 7 days after soil drench-application of a chemical trigger, benzothiadiazole (BTH). Elicitation of plant immunity was confirmed by significant up-regulation of four genes, CaPR1, CaPR4, CaPR9, and CaCHI2, by BTH treatment. Bacterial fitness was evaluated by measuring growth rate during cultivation with LE from BTH- or water-treated leaves. LE from BTH-treatment significantly inhibited bacterial growth when compared to that from the water-treated control. The antibacterial activity of LE from BTH-treated samples was not affected by heating at $100^{\circ}C$ for 30 min. Although the antibacterial molecules were not precisely identified, the data suggest that small (less than 5 kDa), heat-stable compound(s) that are present in BTH-induced LE directly attenuate bacterial growth during the elicitation of plant immunity.

• 전기학회논문지P
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• 제59권4호
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• pp.358-363
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• 2010

This paper proposes a step-by-step method of determining the parameters of equivalent circuit which is considered the no load losses for the single phase induction motor which has the starting winding. This method is comprised of three steps, and the stator resistance which is measured by the method of voltage drop is treated as constant and the stator and the rotor leakage reactances are assumed to be the same in every step. The test results of no load and locked rotor test are used in the 1st and 2nd step, and the ratings of name plate of the motor are needed in the 3rd step. In the 1st step, the traditional equivalent circuit parameters are directly calculated by no load and locked rotor conditions. In the next step, five nonlinear simultaneous equations for five unknown parameters can be set up by no load and locked rotor equivalent circuits. These equations are solved by using the initial parameters obtained by the 1st step parameters. In the final step, three nonlinear simultaneous equations for rotor winding resistance, leakage reactance and no load losses component resistance can be set up by equivalent circuit under the rated operation. Three parameters are solved by using the 2nd step parameters. Thus, equivalent circuit parameters are gradually refined step by step. The validity of the proposed method is evaluated by comparing the computed values obtained by the equivalent circuit parameters with the experimental values of the load test.