• 전력전자학회논문지
• /
• 제25권2호
• /
• pp.152-155
• /
• 2020

This study proposes an input filter for a gallium-nitride-based direct matrix converter with a stepless current commutation technique. Various current commutation strategies have been adopted for reliable operation of switches. These strategies are complex to be implemented and require additional components. The stepless current commutation technique is simple to operate but causes overcurrent issues due to the occurrence of short circuit on input sources. In this study, to restrict the short circuit current, we utilized GaN devices with fast switching properties and modified the input filter. The proposed input filter was verified by experimental results of induction motor drive.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2005년도 추계학술대회논문집
• /
• pp.301-305
• /
• 2005

This paper introduces a novel technique to detect and isolate the failures of multiple actuators connected to a system. Failure of actuator considered in this study could be any type of erroneous input that is different from commanded one. The interaction matrix technique allows the development of input-output equations that are only influenced by one target input. These input-output equations serve as an effective toot to monitor the integrity of each actuator regardless of the status of the other actuators. The method is capable of real-time actuator failure detection and isolation under any type of input excitation. The laboratory experiment using 8-bay NASA truss structure verifies the feasibility of the proposed method.

• 한국정밀공학회지
• /
• 제12권5호
• /
• pp.157-165
• /
• 1995

In this paper the comparison between the neural networks and traditional approaches as nonlinear system identification methods are considered. Two model structures of neural networks are the state space model and the input output model neural networks. The traditional methods are the AutoRegressive eXogeneous Input model and the Nonlinear AutoRegressive eXogeneous Input model. Computer simulation for an analytic dynamic model of a single input single output nonlinear system has been done for all the chosen models. Model validation for the obtained models also has been done with testing inputs of the sinusoidal, ramp and the noise ramp.

• 한국정밀공학회지
• /
• 제14권9호
• /
• pp.108-115
• /
• 1997

This paper presents a robust controller design for uncertain nonlinear systems with input saturation. In actual application, the robust controller may require a high input torque so that it faces input saturation due to power limitation of the system. The satruation problem may cause instability of the system. To improve this problem, a robust controller using a fuzzy logic control is proposed. The proposed controller keeps state errors bounded. To validate the proposed controller, an invert pendulum and its control system is set up. The experimental result shows bounded angular position errors under saturated input torques.

• 조명전기설비학회논문지
• /
• 제12권1호
• /
• pp.35-44
• /
• 1998

본 연구에서는 전류스트레스 및 필터소자의 용량저감을 고려한 다이오드 정류기의 입력LC필터 설계법을 기술하였다. 입력교류전류의 제3고조파 성분에 대하여 무한한 임피던스를 갖도록 LC병렬 공진회로와 출력측 직류콘덴서로 구성된 새로운 필터를 단위법(Per Unit)에 의해 설계하였다. 제안된 LC필터를 다이오드정류기에 적용하여 정상상태에서 실험한 결과, 입력교류전류의 제3고조파성분을 8.8〔%〕로 감소시켰으며, 입력역률은 종전의 표준형의 입력역률이 0.76인데 비하여 0.913으로 개선시켰다. 또한 필터소지자의 전압.전류용량감소와 함께, 설계된 입력LC필터는 다이오드 정류기계통에 악영향을 미치지 않았으며, 따라서 종래의 표준형 LC필터에 의한 방법과 비교하여 제안된 방법이 83.5〔%〕의 저용량의 필터로도 고역률의 정류가 가능함을 입증하였다.

• 한국멀티미디어학회논문지
• /
• 제14권7호
• /
• pp.924-932
• /
• 2011

터치스크린을 이용한 기기의 보급이 활성화되었지만 터치스크린을 가진 기기에 대한 한글 입력 방식은 키패드를 이용한 버튼식 방식이 대부분이며, 터치를 이용하더라도 기존 쿼티키를 그대로 적용한 인터페이스를 채택하여 터치만 할뿐 기존방식을 벗어나지 못하고 있다. 본 연구에서서는 제한적인 화면의 크기를 갖는 스마트폰과 같은 휴대용 단말기 및 터치스크린을 가진 기기에 사용할 수 있는 한글입력시스템에 대하여 제안하고자 한다. 이는 모든 모음에 한글 창제원리에 맞는 방향성을 할당하여 드래그하는 방법으로 모음을 입력하도록 하였다. 모의 실험을 통해 기존의 방식보다 입력에 필요한 한글입력자판을 단순화하면서 한글 입력의 신속성 측면에서 매우 효율적임을 확인할 수 있었다.

• 한국정밀공학회지
• /
• 제14권4호
• /
• pp.104-109
• /
• 1997

A robust controller design to corrdinate a robot manipulator under unknown system parameters and bounded disturbance inputs is presented in this paper. Generally, robust controllers require high input torque so that they may face input saturation in actual application due to the power limitation of the actuator. To solve this problem, an improved robust controller with saturated input torque using a fuzzy logic control is proposed. Numerical examples are shown to validate the proposed controller using two degree-of-freedom planar arm.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
• /
• pp.421-425
• /
• 2004

연구개발의 성과를 체계적으로 가시화하는 데는 많은 어려움이 존재한다. 이러한 적용상의 문제점은 연구개발의 input, output, outcome의 개념을 도입하여 Input-Output-Outcome Roadmap 작성으로 해소될 수 있다. 본 연구에서는 지하수 오염저감기술 연구사업에 대한 적용을 통하여 사업의 경쟁력 및 사업성을 확보를 위한 연구개발 성과의 체계적 지표를 제시하였다.

• 대한전기학회논문지
• /
• 제38권6호
• /
• pp.431-440
• /
• 1989

This paper proposes a new PWM cycloconverter which can step up input voltage. With input reactors ac power supply acts as current source, and with output capacitors the balanced output voltage is build-up. The converter is modeled with fourth order state equation using dq transformation and the steady state characteristics are evaluated. It is shown that the proposed converter can generate the output voltage 2-5 times greater than input voltage. The output voltage and input current have sinusoidal and smooth waveforms and the converter is capable of voltage build-up. The characteristics of the proposed converter is verified simulation and experiment.

• Journal of Power Electronics
• /
• 제18권4호
• /
• pp.1015-1026
• /
• 2018

A family of dual-DC-input (DI) dual-buck inverters (DBIs) is proposed by employing a DI switching cell as the input of traditional DBIs. Three power ports, i.e. a low voltage DC input port, a high voltage DC input port and an AC output port, are provided by the proposed DI-DBIs. A low voltage DC source, whose voltage is lower than the peak amplitude of the AC side voltage, can be directly connected to the DI-DBI. This supplies power to the AC side in single-stage power conversion. When compared with traditional DBI-based two-stage DC/AC power systems, the conversion stages are reduced, and the power rating and power losses of the front-end Boost converter of the DI-DBI are reduced. In addition, five voltage-levels are generated with the help of the two DC input ports, which is a benefit in terms of reducing the voltage stresses and switching losses of switches. The topology derivation method, operation principles, modulation strategy and characteristics of the proposed inverter are analyzed in-depth. Experimental results are provided to verify the effectiveness and feasibility of the proposed DI-DBIs.