• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.329-332
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• 2005

In this paper, we describe implementation of personal media gateway (PMG) for applications over BcN networks. PMG is a TV based set-top terminal, which enables transmission of Full D1 high quality video and audio at the speed of maximum 2Mbps. It supports SIP protocol and QoS for the BcN networks. The hardware of the PMG consists of host module, audio/video codec processing module, DTMF module, and remote control I/O module. H.263 and MPEG4 software are implemented in DSP as codec for hi-directional communication and streaming, respectively. G.711 and Ogg-Vorbis are implemented as audio codec. We examined the quality of video using the Video Quality Test Equpment, which was developed by KT Convergence Lab. The experimental results show the video quality of MOS 4.1 and audio quality of MOS 4.3. We expect that PMG will be prospective business models, and create new customer value.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.3
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• pp.127-133
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• 2004

This paper presents a prototype of three-phase current source zero voltage soft-switching PWM controlled PFC rectifier with Single Active Auxiliary Resonant Commutated Snubber (ARCS) circuit topology. The proposed three-phase PFC rectifier with sinewave current shaping and unity power factor scheme can operate under a condition of Zero Voltage Soft Switching (ZVS) in the main three phase rectifier circuit and zero current soft switching (ZCS) in auxiliary snubber circuits. The operating principle and steady-state performances of the proposed three-phase current source soft-switching PWM controlled PFC rectifier controlled by the DSP control implementation are evaluated and discussed on the basis of the experimental results of this active rectifier setup.

• Journal of Sensor Science and Technology
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• v.19 no.5
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• pp.349-355
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• 2010

Stroke patients, etc. can't use their hands because of the paralysis of their fingers, and their fingers could be recovered by rehabilitating training. In order to judge the rehabilitating extent of their fingers, the patients should grasp a cylindrical object in hospital. At present, the used object in hospital is only a cylindrical object, and can't measure the force of fingers. Therefore, doctors judge the rehabilitating extent by touching and watching at their fingers. So, the four-finger force measuring system which can measure the force of their fingers should be developed. In this paper, four-finger force measuring system with four force sensors which can measure the grasping force is developed. The force sensors are designed and fabricated, and the force measuring device is designed and manufactured by using DSP(digital signal processing). Also, the grasping force test of men is performed by using the developed four-finger force measuring system. It was confirmed that the finger average force of right hand is about 214.6 N and that of left hand is about 212.8 N.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.385-388
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• 2001

In this paper, the gearless traction machine drive system using a permanent-maget motor for high-speed elevators is addressed. This application of permanent-magnet motor to the elevator traction machine enables several improvements including higher efficiency, better ride comfort, smaller size and weight, and so on. PWM boost converter is also adopted so that DC-link voltage regulation, hi-directional power flow, and controllable power factor with reduced input current harmonics are possible. To increase reliability and performance, the control board, which can include the car and group controller as well as PWM converter and inverter controller, is designed based on TMS320VC33 DSP The simulator system for high-speed elevators has been developed so that the drive system of high-speed elevator can be tested without my limitation on ride distance and the load condition. Some experimental results are given to verify the effectiveness of the developed system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.128-135
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• 2004

The author present a modified multi-loop algorithm including feedforward for controlling a 55kW step down chopper in the power supply of Maglev. The control law for the duty cycle consists of three terms. The first is the feedforward term. which compensates for variations in the input voltaga. The second term consists of the difference between the slowly moving inductor current and output current. The third term consists of proportional and integral terms involving the perturbation in the output voltage. This perturvation is derived by subtracting the desired output voltage from the actual output voltage. The proportional and integral action stabilizes the system and minimizes output voltage error. In order to verify the validity of the proposed multi-loop controller, simulation study was tried using Matlab simulink

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1896-1897
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• 2007

Medical equipment of high frequency has been presently applied to various parts of human body and novel treatment effects have been shown by it. Recently there are many cases that high frequency apparatus has been used in dermatology as the interest in beauty has been growing. Especially used in skin, blood volume is increased by keeping surface temperature of skin at around $43^{\circ}C$ and domodex folliculorum are treated by applying high electric field. It is the aspect we consider that increasing blood volume and domodex folliculorum treatment take effect on hair loss. In this study, high frequency electrotherapy apparatus was proposed to be applied to hair loss treatment. For that, human body was experimented with varying output voltage and frequency. The adjustable switching signal for treatment was obtained from 100[kHz] to 1000[kHz] by using DSP. Stable output specific was also obtained by feedback control to protect human body. The best hair growth conditions were the output voltage of 1.2[kV], the frequency of near 300[kHz] and the maximum current of 2[mA]. We apply this high frequency electrotherapy apparatus to two bald men, 46-year-old and 45-year-old. After treatment for a month they had thick and strong hair.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.987-990
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• 2003

산업현장에서의 인터넷환경 및 원격 제어를 위한 시스템 개발에서 신뢰성이 있고 경제적이며 지능적인 Power Supply가 요구되고 있다. 최근 통신시스템의 Power Supply는 수 kA이상의 출력전류를 가지고 있으며 최소 10개 이상의 모듈로 이루어져 있다. High-End 서버 시스템과 같이 수백 개의 마이크로프로세서를 내장한 시스템은 수십 kW의 전력을 소모한다. 이들이 사용하는 Power Supply는 별도의 시스템 제어기와의 통신으로 시스템에서 발생하는 발열, 소모전력, Total Harmonic Distortion (THD)에 대한 정보를 바탕으로 시스템이 갖는 각각의 Module에 대해 효과적이고 신뢰성 있는 전력공급을 하여야 만다. Distributed Power System (DPS)에서 가장 중요만 역할을 담당하는 Power Factor Correction (PFC) AC-DC Converter의 디지털 제어는 시스템 제어기와의 통신능력을 충분히 고려하면서 DPS를 위한 적합한 솔루션을 제공할 것이다. 본 논문에서는 Digital Signal Processor (DSP)를 사용하여 PFC 제어에 필요한 전파정류전압, 입력전류, 출력전압을 계측하여 역률개선과 THD의 저감을 위한 전류의 추종을 제어하면서 이들 제어기에서의 파라미터를 PC를 통해 모니터하여 최근의 추세를 만족시킬 수 있는 시스템을 구현할 수 있을 것으로 사료된다.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.8
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• pp.157-164
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• 2000

This paper presents a method to detect a rotor position and to drive a BLDC motor from standstill to medium speed without any position sensor comparing the current responses due to the inductance variation in the rotor position. A rotor position at a standstill is identified by the current responses of six pulses injected to each phase of a motor. Once the motor stars up pulse train that is composed of long and short pulses is injected to the phase corresponding to produce the maximum torque and the next phase continuously. it provides not only the torque but also the information of the next commutation time effectively when the response of long and short pulses crosses each other after the same time delay. This method which is verified experimentally using a DSP can drive a BLDC motor to the medium speed smoothly without any rattling and time delay compared with the conventional sensorless algorithm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1166-1171
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• 2001

The method for output disturbance estimation is proposed. In this method, output disturbance is estimated from the closed loop system dynamics using the output and control input signals. In the closed-loop output-disturbance estimator, precise system identification is required to reduce estimation error. The realization of estimator was done by the DSP board (DSPl103), and disturbance estimation in various environments was performed： change of rotation speed, media feature and spindle motor with (or without) auto-ball balancing system (ABS). From these experiments, the disturbance characteristics of ODD under various conditions are analyzed, and the desirable servo loop configuration based these results is proposed.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.2
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• pp.75-81
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• 2021

This study analyzes the resonance characteristics caused by the mutual interference between LCL filters and the grid impedance under the parallel operation of the grid-connected inverter using the LCL filter. These characteristics are verified through simulation and experiment. Two inverters are used to connect to the grid in parallel, and the system parameters, including the LCL filter, are set to the same conditions. In the case of inverters running in parallel at the point of common coupling, the presence of grid impedance causes mutual interference between the LCL filters of each inverter, and the deviation of the filter resonance frequency is analyzed to understand the parallel inverter. The correlation between the number of devices and the size of grid impedance is simulated by PSIM and verified by MATLAB. By connecting the real-time digital simulator Typhoon HILS to the DSP 28377 control board, the mutual interference characteristics are tested under the condition of two inverters running in parallel. The experimental and analysis results are the same, indicating the validity of the analysis.