• 대한전자공학회논문지SD
• /
• 제41권7호
• /
• pp.89-96
• /
• 2004

넓은 범위의 전압-제어 발진기 및 자동 이득 조절기의 실현을 위한 고선형 전압-제어 전류원(VCCS) 회로를 제안하였다. 제안한 VCCS는 전압 입력을 위해 이미터 폴로워, 전류 출력을 위해 이미터가 결합된 두 개의 공통-베이스 증폭기, 그리고 넓은 범위의 전류 출력과 높은 선형성을 얻기 위해 두 증폭기를 결합한 전류 미러로 구성된다. VCCS의 회로는 별도의 바이어스회로가 없이 단지 5개의 트랜지스터와 1개의 저항기만 사용하였다. 시뮬레이션 결과 제안한 VCCS는 5V의 공급전압에서 1V에서 4.8V까지의 제어-전압에 대하여 최대 0A에서 300㎃까지의 전류를 출력할 수 있다. 0㎃에서 300㎃의 출력 전류의 최대 선형 오차는 1.4 %이였다.

• 조명전기설비학회논문지
• /
• 제26권6호
• /
• pp.16-28
• /
• 2012

This paper proposes a quasi Z-source converter(QZSC) with a diode-capacitor output filter to improve the output DC voltage boost ability. The proposed converter has the same quasi Z-source network topology compared with the conventional converter. But the proposed method is adopted a diode-capacitor filter as its output filter, since the conventional method is used an inductor-capacitor as its output filter. Under the condition of the same input-output DC voltage, the proposed method has more lower shoot-through duty ratio than the conventional method. Also, because the proposed converter has same voltage boost factor under lower shoot-through duty ratio compared with the conventional converter, the proposed converter can be operated with the lower capacitor voltage of Z-source network and the lower input current. To confirm the validity of the proposed method, PSIM simulation and a DSP based experiment were performed to acquire the output DC voltage 120[V] under the input DC voltage 80[V]. And the capacitor voltage and inductor current in Z-source network, the output voltage of each converter were compared and discussed.

• 한국통신학회논문지
• /
• 제21권6호
• /
• pp.1596-1603
• /
• 1996

A single body type of fiber-optic current and voltae sensor using a rare earth doped YIG and a bismuth silicon oxide single crystsl is proposed, which is used for simultaneous measurement of the AC electric current and AC electric voltage over the trasmission lines. Experimental results showed that the fiber-optic current sensor has the maximum 7.5% error within the current range of 0A to 400A, and the fiber-optic voltage sensor has the maximum 0.87% error within the current range of 0V to 400V. The output waveforms of proposed fiber-optic sensor system has a good agreement with output waveforms of conductor current and voltage. Experimental results proved that the output of fiber-optic current sensor is not affected by the electric voltage applied to the fiber-optic voltage sensor, and also, that the output of fiber-optic voltage sensor is not affected by the electric current applied to the fiber-optic current sensor.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
• /
• pp.1436-1439
• /
• 2005

A novel current-type data driver for active matrix organic light emitting diode (AMOLED) is proposed for current uniformity enhancement among its output channels. New architecture is composed of shadow DACs that precharge output stages, a single-real DAC that correct the output level to a real target current level and output stages that operate in 3 states of sampling, correcting and driving. Simulation results show that the proposed driving method and circuits improve the current uniformity among output channels of a current-type driver IC.

• Journal of Power Electronics
• /
• 제13권1호
• /
• pp.20-30
• /
• 2013

This paper presents a soft switching DC/DC converter for high voltage application. The interleaved pulse-width modulation (PWM) scheme is used to reduce the ripple current at the output capacitor and the size of output inductors. Two converter cells are connected in series at the high voltage side to reduce the voltage stresses of the active switches. Thus, the voltage stress of each switch is clamped at one half of the input voltage. On the other hand, the output sides of two converter cells are connected in parallel to achieve the load current sharing and reduce the current stress of output inductors. In each converter cell, a half-bridge converter with the asymmetrical PWM scheme is adopted to control power switches and to regulate the output voltage at a desired voltage level. Based on the resonant behavior by the output capacitance of power switches and the transformer leakage inductance, active switches can be turned on at zero voltage switching (ZVS) during the transition interval. Thus, the switching losses of power MOSFETs are reduced. The current doubler rectifier is used at the secondary side to partially cancel ripple current. Therefore, the root-mean-square (rms) current at output capacitor is reduced. The proposed converter can be applied for high input voltage applications such as a three-phase 380V utility system. Finally, experiments based on a laboratory prototype with 960W (24V/40A) rated power are provided to demonstrate the performance of proposed converter.

• 대한전자공학회논문지SD
• /
• 제48권11호
• /
• pp.48-56
• /
• 2011

전기적인 조정(tuning) 시스템에 사용하기 위해, 차동출력을 갖는 새로운 A급 $CCII{\pm}$와 이를 이용한 출력 전류 제어가능한 CCII+를 설계하였다. 설계한 $CCII{\pm}$는 종래의 CCII+와 상보적인 교차 전류원으로 구성된다. 또한, 출력 전류 제어가능한 CCII+는 제안한 $CCII{\pm}$와 단일 출력을 갖는 전류 이득 증폭기로 구성된다. 시뮬레이션 결과 $CCII{\pm}$는 $1.9{\Omega}$의 전류 입력단자의 임피던스와 우수한 전압 및 전류 폴로워 특성을 갖고 있다는 것을 확인하였다. 제안한 CCII+는 $100{\mu}A$에서 10mA의 바이어스 제어 전류 범위에서 10MHz의 3-dB 주파수을 갖고 있으며, 출력 전류 제어 범위는 4-디케이드(decade)이다. CCII+의 전력소비는 ${\pm}2.5V$ 공급전압에서 4.5mW이다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.215-218
• /
• 2001

In conventional three-phase rectifiers, it was necessary to use a transformer to obtain low output voltage. In this paper, we propose a new three-phase rectifiers circuit that achieves low voltage by using a very simple circuit configuration that does not have a transformer and does not need any complex control. We also describe the operation principle of the proposed circuit, and derive a theoretical formula for its current waveform. On the basis of this formula it also explores the theoretical input/output current characteristics, theoretical current amplification factor, and theoretical output voltage characteristics of these theoretical values with experimentally obtained input/output current characteristics, current amplification factor, and output voltage characteristics, allowed us to confirm the soundness of our theoretical analyses.

• 대한전기학회논문지
• /
• 제45권1호
• /
• pp.30-41
• /
• 1996

Current Source(CS) PWM converter is appropriate for the magnet power supply system which requests high power and high precision current control. Input and output filters should be installed to eliminate the current or voltage harmonics caused by the PWM switching for the CS PWM converter. But the input/output filters limit the output DC current range and may destroy the system with filter resonance, and make the system equation more complicated. In this paper, systematic and simple filter design method which considers not only the harmonic attenuation but also the total system good transfer function characteristics in the dc filter. The simulated and experimental results verify the proposed theory. (author). refs., figs., tabs.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2012년도 전력전자학술대회 논문집
• /
• pp.242-243
• /
• 2012

In this paper, 200 W power supply for LED driver has been designed, analyzed, simulated and tested. Input AC voltage of 100VAC-240VAC was converted to DC voltage by high power factor converter. Output voltage was controlled, and output current was controlled by constant current when output current was reached to LED maximum rated current. By simulation and experimental test, voltage and current control and high power factor characteristics are verified.

• 전력전자학회논문지
• /
• 제23권3호
• /
• pp.208-216
• /
• 2018

In this paper, an LLC resonant converter employing two coupled inductors on the secondary side of the converter is proposed. The conventional LLC converter exhibits serious power loss during secondary winding of the transformer because of generation of tremendous output current ripples. To overcome this problem, an LLC resonant converter with a current doubler as a rectifying circuit was recently proposed. However, the current-doubler rectifying circuit requires coupled inductors with a high coupling ratio to retain the designed resonance characteristics. Therefore, an additional hardware filter is required at the output stage to address large output current ripples. Additional design procedures are also necessary because the inductance component of the added filter affects the designed resonant network. To solve this issue, an LLC resonant converter employing two coupled inductors is proposed in this paper. Mathematical analysis shows that the proposed secondary-side current-doubler circuit does not affect the designed resonance characteristics. The operating principles and theoretical analyses are proven through a simulation and experiments with a 54 V/28 A prototype.