• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1990년도 추계학술대회
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• pp.118-121
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• 1990

This paper describes development of an implantable power switching system for biotelemetry system. This system is designed and manufactured to achieve as small size and low power dissipation as possible, using pulse powered circult and CMOS technology. The function of the power switching system is to connect the implantable battery to implanted sensors and, electronics systems by receiving intermittent command signals from external circuits. The power dissipation of this system was about $15{\mu}W$ for a stand-by operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1022-1024
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• 2015

An auxiliary switching power supply is designed for the control circuit of a machine integrated with frequency variation based on TOP249Y in this paper. And experiments have been conducted to verify that this power supply can function well even with fluctuating inputs, indicating the validity of this switching power supply and it can be applied to supply some other electrical equipments.

• 대한안전경영과학회지
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• 제5권2호
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• pp.199-214
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• 2003

With the progress of industrial technology, industrial machinery and home appliances have multi-function and high performances by the electronic control technology. Various results are given from the measuring switching induction noise according to environmental condition and its effects cannot be predicted accurately. Therefore, the output results should be analyzed and applied to practical work. To minimize the false operation, Taguchi Method used to solve the quality problem is adopted to analyze the characteristics within the constrained measuring level.

• 한국태양에너지학회 논문집
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• 제39권2호
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• pp.81-92
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• 2019

When Photovoltaic inverter is connected to grid and used as PVPCS (Photovoltaic Power Conditioning System), 120 Hz AC ripple occurs at the dc-link capacitor voltage. This AC ripple reduces the efficiency of PVPCS and shortens the lifetime of the capacitor. In this paper, we design a notch filter to remove AC ripple. As a result, the AC voltage ripple was removed from the dc link and the THD of the PVPCS output current with the notch filter was lowered. This notch filter is determined by the damping coefficient, the bandwidth coefficient, and the switching frequency. Among these, the switching frequency determines the switching loss and the size of the LC filter, and the PVPCS with the high switching frequency has a greater efficiency loss due to the switching loss than the efficiency improvement by the notch filter. Therefore, it is important to set the optimum switching frequency in the PVPCS with the notch filter applied. In this paper, THD and switching loss of PVPCS output current with notch filter are calculated through simulation, and cost function to calculate optimum switching frequency through data is proposed.

• 한국해양공학회지
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• 제17권4호
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• pp.59-65
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• 2003

In order to achieve the desired lightweight and robust design of a structure, it is preferable to design a structure and its control system, simultaneously, which is termed the combined optimal design. A constant-cross-sectional area cantilever beam was chosen as the optimum design method, An initial load and a time-varying disturbance were applied at the free end of the beam. Sliding mode control was selected, due to its insensitivity to the disturbance, compared with other modes. It is known that the sliding mode control is robust to the disturbance and is uncertain, only if a matching condition is met, after giving a switching hyper plane. In this study, the optimum method was used for the design of the switching hyper plane, and the objective function of the optimum switching hyper plane was assumed to be the objective of the control system. The total weight of the structure was treated as a constraint, and the cross sectional areas of the beam were considered as design variables, the result being a nonlinear programming problem. To solve it, the sequential linear programming method was applied. As a result of the optimum design, the effect of attenuating vibrations has been substantially improved. Moreover, the lightweight design of the structure became possible as a result of the relationship of the weight of the structure to the control objective function.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.488-491
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• 1995

The paper presents a new global maximum search method for multimodal unknown functions of two variables. The search method is composed of two stages and sequentially samples the candidate point in a subdomain selected using a priority function in each stage. The search domain is auto-similarly divided into triangular subdomains, or cells, during the search process. A measure of accuracy of local maximum search is introduced to check if a local search has converged to a specified accuracy or the maximum of a local peak cannot be the global maximum. A criterion for switching from the first to the second stage, is proposed using a ratio of the observed peak width to the largest cell in the domain. By numerical simulations, the required number of trials is evaluated for some function models with different peak parameters, and the switching criterion is optimally determined. The results show that the proposed method obtains global maximum points with certainty and saves largely computation time even for functions with extremely steep peaks.

• 한국정밀공학회지
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• 제19권10호
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• pp.45-51
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• 2002

To achieve the lightweight and robust design of a structure, it is requested to design a structure and its control system simultaneously, which is called as the combined optimal design. A constant-cross-sectional area cantilever beam was chosen as an example for the applying the optimum design method. An initial load and a time varying disturbance were applied at the free end of the beam. Sliding mode control was selected due to its insensitiveness to the disturbance compared with other modes. It is known that the sliding mode control is robust to the disturbance and the uncertainty only if a matching condition is met, after giving a switching hyper plane. In this study, the optimum method was used for the design of the switching hyper plane and the objective function of the optimum switching hyper plane was assumed to be the objective one of the control system. The total weight of the structure was treated as a constraint and the cross sectional areas of the beam were considered as design variables, which means a nonlinear programming problem. The sequential linear programming method was applied to solve it. As a result of the optimum design, the effect of attenuating vibrations has been improved obviously. Moreover, lightweight design of the structure became possible from the relationship of the weight of the structure and the control objective function.

• 전력전자학회논문지
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• 제20권5호
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• pp.421-428
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• 2015

An advanced direct torque control (DTC) with pulse width modulation (PWM) method is presented in this paper. The duty ratio calculation of the selected voltage vector is based on the voltage functions of the selected voltage vector according to the sector angle. The proposed DTC uses a conventional DTC scheme with six sector divisions and switching rules. However, the winding voltages are supplied by the PWM approach. Furthermore, the duty ratio of the switching voltage vector is determined by the flux, torque error, and motor speed. The base voltage that shall determine the duty ratio can be calculated by approximate voltage functions according to the voltage angle. For the calculation of base voltages, second-order quadratic functions are used to express the output voltage of the selected voltage vector according to voltage angle. The coefficients for the second-order quadratic functions are selected by the voltage vector, which is determined by the switching rules of the DTC. In addition, the voltage functions are calculated by the coefficients and voltage angle between the voltage vector and rotor position. The switching voltages from the calculated duty ratio can supply the proper torque and flux to reduce the ripple and error. The proposed control scheme is verified through practical experimental comparisons.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.721-724
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• 2006

본 논문에서는 분할기법을 이용하여 디지털논리스위칭함수를 구성하는 한가지 방법을 제안하였다. 먼저, 디지털논리시스템에 대한 분할기법의 개념을 서술하였고, 본 논문에서 사용되는 각종 정의에 대해 논의하였다. 또한, 제안한 방법으로 구한 디지털논리스위칭함수를 회로설계하기 위해 먼저, 각각의 분할함수에 기초를 둔 Building Block(BB)을 구성에 대해 서술하였다. 그리고 이들 BB를 근간으로 회로설계하는 방법에 대해 논의하였다. 그리고 제안한 방법을 적용 예를 들어 그 결과를 기존의 방법과 비교 및 검토하였다. 그 결과 기존의 방법에 비해 효과적인 cost를 얻을 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.398-399
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• 2019

본 논문에서는 최근에 디지털논리시스템의 회로 구현시에 적용되기 시작한 분할설계기법의 한가지 방법을 제안하였다. 기존의 디지털논리회로설계기법은 적용되는 개별소자를 어떻게 효과적이며 효율적으로 이용하느냐 하는 것이 큰 목적이었으나, 최근의 전자공학의 발달과 회로의 집적도가 높아짐에 따라서 디지털논리설계기법은 각각의 모듈을 구성하고 있는 소자들의 개별소자를 사용하는 것보다는 복잡하더라도 좀 더 경제적이고 다기능의 분할설계기법이 요구되고 있다. 이러한 내용을 근간으로 본 논문에서는 효과적인 분할기법을 이용한 스위칭함수구성의 한가지 방법을 제안하였다.