• 전력전자학회논문지
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• 제26권2호
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• pp.127-134
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• 2021

This study presents an overhang-type rail traction system using dual brushless AC (BLAC) motors with hall sensors. For an accurate position and moving length control of the designed rail traction system, instantaneous position controller using speed reference model and modified disturbance observer for BLAC motor with hall sensor are proposed. The presented speed reference model is designed to satisfy the required performance of 200 mm/s with proper acceleration and deceleration slopes to reduce mechanical vibration. Through the instantaneous speed reference model, instantaneous position and speed errors can be compensated together. Furthermore, the modified disturbance observer for BLAC motors with low-resolution hall sensors can improve the torque and speed control performance. The proposed disturbance observer is based on an actual motor speed. However, the feedback speed information of the hall sensor is not enough for use in the low-speed region. The practical adopted disturbance observer uses an activation speed band to the actual torque controller of the designed rail traction system. The proposed position control scheme is verified by the MATLAB-Simulink model and a practical manufactured traction system. In the computer simulation and experiments, the proposed position control scheme shows advanced control performance.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.791-794
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• 1998

This paper presents a constant gm input stagefor low-voltage rail-to-rail operational amplifier. A proposed scheme uses two current paths to keep sum of the biasing currents of the complimentary input pairs. The op amp was designed in a $0.8\mu\textrm{m},$ n-well CMOS, double-polysilicon and double-metal technology. This achieved in weak inversion. The circuit can operate in power supply voltage from 1.5V up to 3V. An open-loop gain, AV, was simulated as 84dB for 15pF load. An unit-gain frequency, fT was 10MHz.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.457-458
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• 2008

This paper presents an output common mode current compensation method to achieve both constant Gm and constant gain. A conventional rail-to-rail CMOS op-amp with constant Gm was designed by using complementary differential input stage and current compensation skills. But it doesn't operate constant gain, because of output resistance variation. With $0.18{\mu}m$ CMOS process, the simulation results show that the differential gain variation can achieve less than 1.3dB. And a 60dB gain, a 13.5MHz unity gain-frequency, and 1mW power consumption, when operating at 1.8V and 10pF load.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.755-758
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• 2002

This paper presents a second-generation CMOS current conveyor (CCII) consisting of a rail-to-rail complementary N- and P-channel differential input stage for the voltage input, a class AB push-pull stage for the current input, and current mirrors far the current outputs. The CCII was implemented using a double-poly triple-metal 0.6 ${\mu}$m n-well CMOS process, to confirm its operation experimentally. A prototype chip achieves a rail-to-rail swing ${\pm}$2.4 V under ${\pm}$2.5 V power supplies and shows the exact voltage and current following performances up to 100 MHz. Because of its high performances, the CCII proposed herein is quite useful for a building block of current-mode circuits. The applications of the proposed CCII to current-mode filters are also described.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.507-512
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• 2003

The railroad is a means of large transportation which has many latents such as a safety and a regularity. That is a results from various confidential performance tests and evaluations of the system. The railroad system consist of various subsystems - vehicle, power supply, signal, communications, track structures, operations, etc. Among them, as an item of safety evaluation there is a measurement of wheel/rail force, so called a measurement of derailment coefficient. This is a very important item because a derailment of a train will bring about a big accident. Especially it is more important in high speed rail of which operation speed is over two times as fast as existing rail. In this paper, it is introduced to preprocess the wheelset for measuring wheel/rail force of high speed rail, such as to treat a measuring wheelset, its finite element analysis, adhesion of strain gauges and static toad test, running test result of main line.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1663-1668
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• 2010

The terms of track is a train-only line for a train service, in premises of station of a station, that the unit over the track for turnout the track from one track to another track, which it changes the course from the main track that is used for operating a train to the side track, is called a turnout The stick strength of tongue rail is adjusting uniform pressure on the both sides, the adhesion strength between a basic rail and tongue rail has to maintain over 100kg of power value to open over 1mm the ends. This study suggested developing a measuring instrument that can measure a basic rail and the stick strength of a movable rail in according with a switch, such as a switch point, and a performance test. This study ties to be helped that it improves measuring usability for the maintainers through improving quality in a stick measuring instrument, that it solves a technique in the site difficulties through improving a measuring instrument, with reducing the obstacles and expenses.

• 전기학회논문지
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• 제60권3호
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• pp.680-685
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• 2011

Nowadays, in metropolitan railroad, DC feeding system is being generally applied. In order to reduce damages of electro-chemical corrosion caused by stray current and leakage current, in DC feeding system, rail is used as negative-polarity return conductor for traction load current. However, it has problem of rail potential increase and there are no adequate measures to prevent it in domestic. In this paper, we presented fundamental theory and related standards about rail potential increase. And then, we analyzed field testing data and simulated a variety of operations by using PSCAD/EMTDC as an analysis program of power system. In addition, voltage control device is suggested to prevent accidents caused by rail potential increase.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1432-1434
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• 2004

Propelled urban rail transit EMU's standardization/localization business receiving MOCT's assistance for 2001 years since 1995 in KRRI. But. urban rail transit is operated because signaling. electrical power. rail etc. as well as EMU connects each other. Therefore, receive MOCT's assistance since 2001 and is achieving standardization research about urban rail transit's infrastructure including signaling. Specially, is propelling standardization about CBTC way for expansive standardization hereafter in signaling part. Main contents of this urban rail transit's signaling standardization research are as following. - standard specification creation - development of core equipment for standardization specification verification - standard specification completion by core equipment testing & evaluation Is explaining about establishment of scheme and these contents for this urban rail transit's signaling's standard specification creation in this paper.

• 대한전자공학회논문지SD
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• 제44권6호
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• pp.19-27
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• 2007

본 논문에서는 공급전압 변화에 둔감한 Gbps급 저전력 LVDS I/O회로를 설계하였다. 제안된 LVDS I/O는 1.8 V, $0.18\;{\mu}m$ TSMC 공정을 이용하여 설계, 시뮬레이션 및 검증하였다. 설계된 LVDS I/O회로는 송신단과 수신단을 포함한다. 제안하는 송신단은 phase splitter와 SC-CMFB를 이용한 출력버퍼로 구성된다. phase splitter의 출력은 공급 전압이 변화하여도 $50{\pm}2%$의 duty cycle을 가지며 $180{\pm}0.2^{\circ}$의 위상차를 가진다. 출력 버퍼는 SC-CMFB를 이용하여 허용 가능한 $V_{CM}$ 전압 값인 $1.2{\pm}0.1V$을 유지하도록 설계하였다. $V_{OD}$전압 또한 허용범위에서 최소값인 250 mV를 갖도록 설계하여 저전력 동작이 가능하도록 구성하였다 수신단은 38 mV의 히스테리시스 전압값을 가지면서 DC옵셋 전압값이 $0.2{\pm}2.6 V$로 넓은 공통 모드전압 범위가 가능하도록 설계하였고 공급전압 변화에도 rail-to-rail로 복원할 수 있는 기능을 가지고 있다. 또한, 수신단은 1 GHz에서 38.9 dB의 높은 전압 이득을 갖도록 설계하였다.

• 전기학회논문지
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• 제61권3호
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• pp.485-490
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• 2012

Nowadays, in metropolitan railroad, DC feeding system is being generally applied. In order to reduce damage of electro-chemical corrosion caused by stray current and leakage current, in DC feeding system, rail is used as negative-polarity return conductor for traction load current. However, it has problem of rail potential increase and there are no adequate measures to prevent it in domestic. The rise of rail potential leads to damage for human and equipments. To solve the problems, this paper presents fundamental theory and related standards about rail potential increase. And then, we analyzed field testing data and simulated a variety of operations by using PSCAD/EMTDC as an analysis program of power system. In addition, this paper suggests rail potential limit device and addresses how to the device. To verify the effect, simulation of DC feeding system before and after the application of the device is carried out in various cases.