• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1232-1234
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• 2003

The push pull forward converter is a very suitable circuit for low output voltage, high output current applications with a wide input voltage range. This converter can be miniaturized by integrate magnetic components such as the output inductor, the transformer and the input inductor. We considered of the efficiency for the push pull forward converter. Developed the push pull forward converter rating are of $36{\sim}72V$ input and 3.3V/30A output. In this converter. the efficiency was measured by 76.4% at full load and 82.95% at half load. The maximum efficiency is up to 83.% at 200kHz, 11A output.

• Journal of Power Electronics
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• 제10권2호
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• pp.115-124
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• 2010

In this paper, a simple yet efficient auto mode-hop ripple control structure for buck converters with light load operation enhancement is proposed. The converter, which operates under a wide range of input and output voltages, makes use of a state-dependent hysteretic comparator. Depending on the output current, the converter automatically changes the operating mode. This improves the efficiency and reduces the output voltage ripple for a wide range of output currents for given input and output voltages. The sensitivity of the output voltage to the circuit elements is less than 14%, which is seven times lower than that for conventional converters. To assess the efficiency of the proposed converter, it is designed and implemented with commercially available components. The converter provides an output voltage in the range of 0.9V to 31V for load currents of up to 3A when the input voltage is in the range of 5V to 32V. Analytical design expressions which model the operation of the converter are also presented. This circuit can be implemented easily in a single chip with an external inductor and capacitor for both fixed and variable output voltage applications.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.948-950
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• 2003

In this literature, the CMOS current mode fout quadrant differentiator circuit is proposed. The implementation is base on an appropriate input stage that converts the input current into a compressed voltage at the input capacitor ($C_{gs}$) of the CMOS driver circuit. This input voltage use as the control output current which flow to the output node by passing through a MOS active load and use it as the feedback voltage to the input node. Simulation results with level 49 CMOS model of MOSIS are given to demonstrate the correct operation of the proposed configuration. But the gain of the circuit is too low so the output differentiate current also low. The proposed differentiator is expected to find several applications in analog signal processing system.

• 전자공학회논문지S
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• 제34S권12호
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• pp.30-40
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• 1997

This paper presents a design method of fuzzy control systems by clustering the data in the subspace of the input-output produyct space. In the case of servo control, most input-outputdata are concentrated in thye steady-state region, and the the clustering will result in only steady-state fuzzy rules. To overcome this problem, we divide the input-output product space into some subspaces according to the state of input variables. The fuzzy control system designed by the subspace clustering showed good transient response and smaller steady-state error, which is comparable with the reference fuzzy system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.400-402
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• 2008

A new interleaved forward converter, adopting series-input parallel-output structure with a common transformer reset circuit, is proposed in this paper. Series-input structure distributes the voltage stress on switches, which makes it suitable for high input voltage application. Paralleling output stage with an interleaving technique enables the circuit handle large output current and reduces filter size. In addition, since two forward converters share one active-clamp circuit for the transformer reset, its primary structure is simplified. All these features make the proposed converter promising for high input voltage applications with high efficiency and simple structure.

• 한국농공학회지
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• 제39권1호
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• pp.41-47
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• 1997

A geographical resource analysis support system (GRASS) was incorporated to an input and output processor for the agricultural nonpoint source pollution (AGNPS) model. The resulting interface system, GIS-AGNPS was a user-friendly, menu-driven system. GIS-AGNPS was developed to automatically process the input and output data from GIS-based data using GRASS and Motif routines. GIS-AGNPS was consisted of GISAGIN which was an input processor for the AGNPS model, GISAGOUT a output processor for the AGNPS and management submodel. The system defines an input data set for AGNPS from attributes of basic and thematic maps. It also provides with editing modes so that users can adjust and detail the values for selected input parameters, if needed. The post-processor at the system displays graphically the outputs from AGNPS, which may he used to identify areas significantly contributing nonpoint source pollution loads.

• 한국지역지리학회지
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• 제8권4호
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• pp.480-491
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• 2002

본 연구의 목적은 정보가 계약된 조건하에서의 다지역에 대한 지역간 산업연관표를 작성하고 이에 대한 정확성을 평가하는 데 있다. 지역간 산업연관표의 작성 방법은 이미 지난 1950년대 초 Isard 및 Leontief 등에 의하여 개발된 이 후 다양한 기법들이 제시되어왔다. 이들 기법 중에서 정확성 면에서는 실제 조사를 통하여 지역간 산업연관표를 작성하는 것이 가장 바람직하지만, 이 경우 많은 시간과 경비를 부담해야만 하는 현실적 어려움이 수반된다. 따라서 은 연구에서는 정보, 특히 지역수준에서 최종수요 및 지역간 상품의 흐름에 대한 정보가 제약된 조건하에서 우리나라의 전국을 5개 지역으로, 그리고 전 산업을 13개 부문으로 구분하여 비조사방법에 의하여 지역간 산업연관표를 작성하였다. 비조사방법에 의하여 지역간 산업연관표를 작성하는 방법에도 여러 가지가 있지만, 본 인구에서는 기본적인 LQ 기법을 원용하여 이를 다지역 모형으로의 확장을 시도하였다. 끝으로 추정된 투입계수의 정확성을 평가하기 위하여, 특정 지역 투자의 지역 및 지역간 파급효과를 분석하고, 이를 기존의 실제 조사를 통한 투입계수와 비교 해 보았다.

• 대한산업공학회지
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• 제40권1호
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• pp.84-99
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• 2014

In this study, determinant input-output variables are identified for calculating Data Envelopment Analysis (DEA) efficiency scores relating to evaluating the efficiency of government-sponsored research and development (R&D) projects. In particular, this study proposes a systematic framework of design and analysis of experiments, called "all possible DEAs", for pinpointing DEA determinant input-output variables. In addition to correlation analyses, two modified measures of time series analysis are developed in order to check the similarities between a DEA complete data structure (CDS) versus the rest of incomplete data structures (IDSs). In this empirical analysis, a few DEA determinant input-output variables are found to be associated with a typical public R&D performance evaluation logic model, especially oriented to a mid- and long-term performance perspective. Among four variables, only two determinants are identified : "R&D manpower" ($x_2$) and "Sales revenue" ($y_1$). However, it should be pointed out that the input variable "R&D funds" ($x_1$) is insignificant for calculating DEA efficiency score even if it is a critical input for measuring efficiency of a government-sonsored R&D project from a practical point of view a priori. In this context, if practitioners' top priority is to see the efficiency between "R&D funds" ($x_1$) and "Sales revenue" ($y_1$), the DEA efficiency score cannot properly meet their expectations. Therefore, meticulous attention is required when using the DEA application for public R&D performance evaluation, considering that discrepancies can occur between practitioners' expectations and DEA efficiency scores.

• Journal of Power Electronics
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• 제19권1호
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• pp.89-98
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• 2019

This paper analyzes the input side performance of a conventional three-phase to single-phase matrix converter (3-1MC). It also presents the input-side waveform quality under this topology. The suppression of low-frequency input current harmonics is studied using the 3-1MC plus capacitance compensation unit. The constraint between the modulation function of the output and compensation sides is analyzed, and the relations among the voltage utilization ratio and the output compensation capacitance, filter capacitors and other system parameters are deduced. For a 3-1MC without large-capacity energy storage, the system performance is susceptible to input voltage imbalance. This paper decouples the inner current of the 3-1MC using a Lyapunov function in the input positive and negative sequence bi-coordinate axes. Meanwhile, the outer loop adopts a voltage-weighted synthesis of the output and compensation sides as a cascade of control objects. Experiments show that this strategy suppresses the low-frequency input current harmonics caused by input voltage imbalance, and ensures that the system maintains good static and dynamic performances under input-unbalanced conditions. At the same time, the parameter selection and debugging methods are simple.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1496-1499
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• 1996

A nonlinear tracking control technique developed for the control of nonlinear systems has been applied to the autopilot design of missile system. The difficulties in the application of inversion based control methods such as input-output feedback linearization and sliding mode control due to nonminimum phase characteristics are discussed. To avoid the stability problem associated with unstable zero dynamics, the input-output feedback linearization is applied with output-redefinition method to normal acceleration control. The output-redefinition method gives an indirect way to apply the nonlinear controls to nonminimum phase plants by redefining the plant output such that the tracking control of the modified output ensures the asymptotic tracking of the original output. The numerical simulation shows satisfactory results both for nominal and for slightly perturbed missile systems adopting the sliding mode control technique. However, the robustness problem in this method is briefly investigated and verified with the simulation.