• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.177-180
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• 2003

본 논문에서는 dc-dc convertor의 진단을 위해 buck 컨버터의 등가 모델을 가정하고 주요 파라메터를 시스템 식별 기법을 통해 추정하였으며 추정된 결과가 실제 시스템의 특성을 충실히 반영하는지를 계측기를 통한 주파수 응답 측정 결과와 비교하여 검증하였다. dc-dc 컨버터의 모델 파라메터 추정을 통해 주요 진단지수를 계산할 수 있으며 진단 지수를 이용하여 시스템의 열화 여부를 판단할 수 있음을 확인 하였다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.968-969
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• 2015

This paper proposes a novel analysis method for calculating inverter DC bus capacitance and line reactor parameters. In the realization process, DC bus capacitance parameter, and ripple current, life of DC bus capacitor, interaction between DC bus capacitance can be calculated by using Newton-Raphson procedure. The design scheme of DC bus capacitor and line reactor, specific parameters such as capacitance, loss, ripple current, central average temperature, life, ripple current, loss, size, central temperature of the reactor were given. Simulation results show that this scheme can accurately calculate the DC bus capacitance and line reactor parameters. Compared with calculation result of references, cost and volume are half. The indicators meet the demand of practical engineering. It had affirmed precision of the analytical method and verified correctness and feasibility of this method.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.6
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• pp.716-722
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• 2014

In order to design the speed controller of the DC motor system, firstly, parameters estimation of the system must be preceded. In this paper, we proposed the application of genetic algorithm(GA) optimization in estimating the parameters of DC motor. Estimated models are considered both first and second order models, and each estimated model is optimized by minimizing three different types of the evaluation function of GA. Also, GA is imported in comparison with estimation result of numerical analysis method because of its power in searching entire solution space with more probability of finding the global optimum. Data for parameter estimation is acquired from input and output signals of the actual experiment device and the butterworth filter also designs for removing noise in the signals. Finally comparison between real data of the actual device and estimated models is presented to indicate effectiveness and resolution of proposed identification method.

• Journal of the Korean Magnetics Society
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• v.13 no.5
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• pp.216-220
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• 2003

In this work, transmission characteristics of read and write signal were calculated when a MRAM (magnetic random access memory) cell is operated up to 10 GHz. Test device having long read and write lines was modeled in 3 dimensions to perform a simulation. The simulation was divided into two parts, read and write operations, and S-parameters were computed utilizing FEM (finite element method) algorithm. Transmission coefficients, S$\sub$21/, for read and write operations of MRAM device which was designed for a single cell test configuration were analyzed from DC to 1 GHz and DC to 10 GHz, respectively. When the insulator thickness between the bit and sense lines was increased from 500 to 1500 ${\AA}$, 3 dB attenuation frequency was increased by 3.3 times, from 135 to 430 MHz. The length of the bit and sense lines were 600 ${\mu}$m. In addition, access time was estimated by calculating the propagation delay utilizing S-parameters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.7
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• pp.1009-1017
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• 1993

The Robust Adaptive Servo Controller in this paper has an error-corrected and robust structure which guarantees asymptotic regulation and tracking in the presence of bounded parameter perturbations. The adaptive mechanism tunes the controller parameters such that a quadratic performance index is minimized. Through the speed and position control of the DC servo model with computer simulations, the minimum variance controller parameters are robust with respect to finite parameter perturbation and bounded disturbance.

• Journal of Power Electronics
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• v.12 no.3
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• pp.399-409
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• 2012

In DC-DC Buck converters with average current mode control, the current loop compensator provides additional design freedom to enhance the converter current loop performance. On the other hand, the current loop circuit elements append substantial amount of complexity to not only the inner current loop but also the outer voltage loop, which makes it demanding to quantify circuit and operating parameter effects on the small-signal dynamics of such converters. Despite the difficulty, it is shown in this paper that parameter effects can be analyzed satisfactorily by using an existing small-signal model in conjunction with a newly proposed simplified alternative. As a result of the study, new insight into average current mode control is uncovered and discussed quantitatively. Measurable experimental results on a prototype averaged-current-mode-controlled Buck converter are provided to facilitate the analytical study with good correlation.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.852-854
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• 1995

This paper proposes a new identification method that utilizes fuzzy inference in parameter identification. The prosed system has an additional control loop where a real plant has replaced by a plant model. Fuzzy rules describe the relationship between comparison results of the features and magnitude of modification in the model parameter values. In this paper, the tuning method which determines parameters of PID controller automatically is described through applying this algorithm to DC servo motor. And we intend to investigate effectiveness of the method by experiments. This method is effective in auto-tuning because the response of the closed loop has verified. The simulated and the experimental results of the dc servo motor are shown to confirm the viability of this method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.432-438
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• 2001

In this paper, after applying Defected Ground Structure(DGS) to DC block, changes of gap and length of λ/4 coupled line are investigated by EM simulation and fabrication. As a result, on condition of the same output with the case using typical DC block, the gap between λ/4 coupled line is widen from 0.1 mm to 0.46 mm by 0.36 mm and the length of λ/4 coupled line gets shorter from 17.7 mm to 13.2 mm by 4.5 mm. Also three type power amplifiers using blocking capacitor, typical DC block and DGS DC block are fabricated and investigated. At first, when S parameter characteristics of each amplifier are considered at frequency band of 3.2 +-0.O5 GHz, every amplifier has similar characteristics of gain and S parameter. Second when the output power of amplifiers is 25 dBm after putting CW signal of 3.2 GHz into three type amplifiers, the difference of dominant signal and 2nd harmonic signal using blocking capacitor, typical DC block and DGS DC block is each -44.83 dBc, -66.84 dBc and -64.33 dBc. Therefore harmonic characteristics of amplifiers using typical DC block and DGS DC block is almost same.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.05a
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• pp.51-54
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• 2003

반도체 산업의 발전에 따라 생산과정에서의 반도체 소자의 특성을 검사하고, 오류를 검출하는 작업을 효율성 있게 하여 생산성을 향상시키는 것이 더욱 중요시 되고 있다. 이러한 흐름에 맞추어 반도체 test장비에 VFCS(voltage forcing current sensing)와 CFVS(current forcing voltage sensing)를 test 할 수 있게 개발하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.6
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• pp.531-538
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• 1999

This paper proposes a fuzzy logic controller(FLC) for DC-DC converters in order to obtain good l perfonnances that can not be achieved by linear control tc'Chniques in the presence of wide parameter v variations. 'While the standard controller uses error and derivative of e$\pi$or, the proposed controller uses state v variables. Such method is ve$\pi$ efficient in case of DC-DC converters and can guarantee both stable s small-signal responses and improved large signal responses. The presented approach method is general and c can be applied to any dc-dc converter topologies. Through the simulations of booster, we verify the pro[Xlsed C control tc'Chnique can give a satisfactory perfonnance.