• 대한안전경영과학회지
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• 제9권5호
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• pp.43-48
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• 2007

This paper is to present linkage parameter to integrate statistical models and physical models for accelerated life test. Statistical models represent the relationship of probability distribution and life. Physical models show the relationship of life and stress. Moreover, this study proposes the four steps for construction of integrated models for accelerated life test using linkage parameter. Finally, this paper develops new integrated models such as extreme value distribution-general Eyring, linearly increasing failure rate function-general Eyring, etc., and estimates various reliability measures.

• Journal of Magnetics
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• 제18권1호
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• pp.57-64
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• 2013

Flux linkage of phase windings is a key parameter in determining the behavior of a switched reluctance motor (SRM) [1-8]. Therefore, the accurate prediction of flux linkage at aligned and unaligned rotor positions makes a significant contribution to the design of an SRM and its analytical approach is not straightforward due to nonlinear saturation in flux. Although several different approaches using a finite element analysis (FEA) or a curve-fitting tool have been employed to compute phase flux linkage [2-5], they are not suitable for a simple design procedure because the FEA necessitates a large amount of time in both modeling and solving with complexity for every motor design, and the curve-fitting requires the data of flux linkage from either an experimental test or an FEA simulation. In this paper, phase flux linkage at aligned and unaligned rotor positions is estimated by means of a reluctance network, and the proposed approach is analytically verified in terms of accuracy compared to FEA.

• Journal of Electrical Engineering and Technology
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• 제5권4호
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• pp.592-596
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• 2010

In a multi-layer interior permanent magnet synchronous motor, the d- and q-axis parameters vary nonlinearly according to different load conditions, consequently changing the level of saturation. The flux-linkage of d- and q-axis conveys ripple characteristics resulting from mechanical structure and degree of magnetic saturation. If the calculated flux-linkage is correct, the torque using the Maxwell stress tensor method is the same torque calculated by the flux-linkage. However, discrepancy between results exists. In this paper, the d- and q-axis flux-linkage, in consideration of the ripple characteristic, is calculated. Simulation results are then compared with experimental results.

• 전력전자학회논문지
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• 제23권1호
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• pp.66-71
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• 2018

We propose an online parameter estimation method for surface-mounted permanent-magnet synchronous motor (SPMSM) using an affine projection algorithm (APA). The proposed method estimates parameters with two APAs based on the discrete-time model equation of SPMSM during motor operation. The first APA is designed to estimate inductance, and the second APA is designed to estimate resistance and flux linkage. However, in case when the d-axis current is controlled to 0A, the second APA cannot estimate resistance and flux linkage simultaneously because the matrix rank in APA becomes deficient. To overcome this problem, we temporarily inject a negative reference current input to the d-axis control loop, and the matrix in the APA then becomes full rank, which enables the simultaneous estimation of resistance and flux linkage. The proposed method is verified by PSIM simulation and an actual experiment, and the results reveal that SPMSM parameters can be estimated online during motor operation.

• 전기전자학회논문지
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• 제26권4호
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• pp.653-658
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• 2022

본 논문에서는 온도 변화로 인한 영구자석 쇄교 자속 변화를 고려한 PMSM 드라이브의 MTPA(Maximum Torque per Ampere) 제어 알고리즘을 제시한다. 영구자석 쇄교 자속은 고정자 쇄교 관측기를 통해 실시간으로 추정되고, 추정된 영구자석 쇄교 자속으로부터 토크 오차 보정 계수가 계산된다. 2차원 MTPA look-up table(LUT)은 토크 오차를 보상하기 위해 영구자석 쇄교 자속 변화를 반영하는 MTPA 전류 궤적을 달성하기 위해 개발되었다. 제안된 PMSM의 MTPA 제어 알고리즘은 시뮬레이션을 통해 검증된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.476-481
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• 2001

In a vacuum circuit breaker mechanism, a spring-actuated linkage system is used to satisfy the desired opening and closing characteristics of electric contacts. Because the opening dynamics of electric contacts is determined by such a linkage system, the stiffness, free length and attachment points of a spring become the important design parameters. In this paper, based on the energy conservation that the total system energy is constant throughout the operating range of a mechanism, a systematic design procedure of determining the spring design parameters is presented. The proposed procedure is applied to the design of an opening spring for satisfying the specified opening characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.830-831
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• 2011

The paper makes an investigation on a speed and stator flux linkage estimator for permanent magnet synchronous motor (PMSM) sensorless drives using the technology of model reference adaptive system (MRAS). The designed estimator including two models and two adaptive estimating laws is proved to be stable by the Popov hyper-stability theory. The speed, the stator flux linkage and the resistance are estimated accurately by the proposed estimator while overcoming the shortcoming of the traditional one. The experiment results demonstrate its effectiveness.

• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.516-523
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• 2013

This paper investigates an improved stator flux linkage observer for sensorless permanent magnet synchronous motor (PMSM) drives using a voltage-based flux linkage model and an adaptive sliding mode variable structure. We propose a new observer design that employs an improved sliding mode reaching law to achieve better estimation accuracy. The design includes two models and two adaptive estimating laws, and we illustrate that the design is stable using the Popov hyper-stability theory. Simulation and experimental results demonstrate that the proposed estimator accurately calculates the speed, the stator flux linkage, and the resistance while overcoming the shortcomings of traditional estimators.

• 대한한의학회지
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• 제24권4호
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• pp.92-101
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• 2003

Background ＆ Aims : The aim of this study was to investigate the change of dominant power with observation of gastric myoelectrical activity and its parameter linkage in electrogastrography. Methods : Electrogastrography was performed on a total of 123 subjects (113 patients with functional dyspepsia, 10 healthy controls) for 30 min in fasting state and 50 min in postprandial state. Average myoelectrical activity per frequency and accumulated electrical activity of 5 min duration in each bradygastria, normogastria, and tachygastria were measured at the moment of frequency switchover of slow wave. Assumed parameter linkages were also investigated among dominant frequency, ％ of normal regularity, and dominant power (or power ratio). Results : Average myoelectrical activity per frequency was highest in bradygastria (mean 1.10-1.47 Volt/s), next highest in normogastria (mean 0.50-0.82 Volt/s), and lowest in tachygastria (mean 0.44-0.47 Volt/s). Average accumulated myoelectrical activity was highest in normogastria (mean 114.90-126.29 Volt/ss), next highest in tachygastria (mean 71.02-90.00 Volt/ss), and lowest in bradygastria (mean 12.93-51.94 Volt/ss). Significance of parameter linkages were noted in dominant frequency (p< 0.01) and in ％ of normal regularity (p< 0.01), but not in dominant power in case of frequency shift from bradygastria to normogastria (p=0.376). Conclusion : Dominant power is not a parameter that reflects the gastric myoelectrical activity related with only gastric contraction. Bradygastric dominant power does not follow the inter-parameter linkage of electrogastrography for gastric motility assessment.

• 대한전기학회논문지
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• 제32권11호
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• pp.379-386
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• 1983

In this paper,the more accurate and simple synchronous machine model is derived by parameter modification method. At first, the flux linkage state space model is composed by redefining the parameters of synchronous machine and considering the saturation effect approximately. After that, this modified model is apply to the power system model and the effects of power system stability is analyzed by this model's characteristics in fault condition. As the result, the modified synchronous machine model shows more accurate and simple than the privious one.