• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2528-2530
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• 2000

In general, Diode makes a major role in electronic circuit. For example, switching of rectifier, cross current of switching rectifier, energy transfer of electronic element and reverse charge of capacitor, voltage insulation, energy feedback from load to power supply, and such as recovery of storaged energy. Generally, We regard power diode as ideal element, but it has a certain boundary actually, specially, We use diode for detecting circuit peak hold voltage signal. It has cut in voltage. It occurs error of measurement value namely. This error, below in region diode voltage drop (0.7v) measurement value is wholesome signal, Specially, We can not get precision data. Therefore, precision level is low between theoretical and measurement data because of error in actual circuit. Conclusionally, In this paper, We define the error concerning to the power diode characteristics which is used detecting of the minute signal, and recommend the method that minimize measurement error.

• 전기학회논문지
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• 제66권7호
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• pp.1059-1065
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• 2017

In this paper, the energy harvester with a piezoelectric materials is modeled as the electric equivalent circuit, and performances of a standard DC method and a Parallel-SSHI method are verified through experiment under variable force and load conditions. Piezoelectric generator consists of mass, damper and spring constant, and it is modeled by electrical equivalent circuit with RLC components. Standard DC and Parallel-SSHI are used as power conversion methods, and standard DC consists of full-bridge rectifier and smoothing capacitor. Parallel-SSHI method is composed of L-C resonant circuit, zero-crossing detector and full-bridge rectifier. In case of simulation under $100k{\Omega}$ load condition, the harvested power is $500{\mu}W$ in Standard DC and $670{\mu}W$ in Parallel-SSHI, respectively. In experiment, the harvested power under $100k{\Omega}$ load condition is $420{\mu}W$ in standard DC and $602{\mu}W$ in Parallel-SSHI. Harvested power of Parallel-SSHI is improved by approximately 40% more than that of standard DC method.

• Journal of Power Electronics
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• 제15권2호
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• pp.366-377
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• 2015

In order to minimize switching losses for high power applications, a boost PFC rectifier with a novel passive lossless snubber circuit is proposed. The proposed lossless snubber is composed of coupled inductors merged into a boost inductor. This method compared with conventional methods does not need additional inductor cores and it reduces extra costs to implement a soft switching circuit. Especially, the proposed circuit can reduce the reverse recovery current of output diode rectifiers due to the coupling effect of the inductor. During turn-on and turn-off operating modes, the proposed PFC converter operates under soft switching conditions with high power conversion efficiency. In addition, the performance improvement and analysis of the operating effects of the coupled inductors were also presented and verified with a 3.3 kW prototype rectifier.

• 한국산학기술학회논문지
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• 제13권4호
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• pp.1789-1796
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• 2012

본 논문에서는 RFID 태그 칩 구동을 위한 새로운 고효율 CMOS 브리지 정류기를 설계하고 해석하였다. 동작 주파수가 높아짐에 따라 증가하는 게이트 누설전류의 주 통로가 되는 게이트 커패시턴스를 회로적인 방법으로 감소시키기 위해 제안한 정류기의 입력단을 두 개의 NMOS로 종속접속형으로 연결하여 설계하였으며, 이러한 종속접속형 입력단을 이용한 게이트 커패시턴스 감소 기법을 이론적으로 제시하였다. 또한 제안한 정류기의 출력특성은 고주파 소신호 등가회로를 이용하여 해석적으로 유도하였다. 일반적인 경우의 $50K{\Omega}$ 부하저항에 대해, 제안한 정류기는 915MHz의 UHF(for ISO 18000-6)에서는 28.9%, 2.45GHz의 마이크로파 대역 (for ISO 18000-4)에서는 15.3%의 전력변환효율을 보여, 915MHz에서 26.3%와 26.8%, 2.45GHz에서 13.2%와 12.6%의 전력변환효율을 보인 비교된 기존의 두 정류기에 비해 보다 개선된 전력변환효율을 보였다. 따라서 제안한 정류기는 다양한 종류의 RFID 시스템의 태그 칩 구동을 위한 범용 정류기로 사용될 수 있을 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1212-1213
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• 2011

PWM(pulse width modulation) rectifier has unit power factor and low harmonic distortion with high power conversion efficiency in entire loading range. These merits of PWM rectifier help the spread of DC distribution system. In addition, if multiple PWM rectifiers can be operated in parallel connection, maintenance process can be simple and reliability of power source can be advanced because of the hot swapping is available. The other way, the load unbalance among rectifiers can force a converter to stop by over current. The surge current by closed circuit composition between rectifiers can force switching devices damage. In this paper, some problems that can occur in case of parallel operation of PWM rectifiers and problem eliminating methods are considered.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.147-148
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• 2011

In this paper, implementation of digital control for critical conduction mode power factor correction (PFC) rectifier is presented. Critical conduction mode is widely used in medium and low power conversion application due to its minimized MOSFET turn-on loss and diode reverse-recovery problem. However, it needs additional zero current detection circuit and maximum frequency limit to properly turn the MOSFET on and avoid the excessive switching loss in light load operation. This paper explains the digital IC implementation and verifies its operation with 200-W prototype PFC rectifier.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.468-472
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• 2007

For small capacity rectifier circuits such as these for consumer electronics and appliances, capacitor input type rectifier circuits are generally used. Consequently, various harmonics generated within the power system become a serious problem. Various studies of this effect have been presented previously. The absence of switching devices makes systems more tolerant to over-load, and brings low radio noise benefits. We propose a power factor correction scheme using a LC resonant in commercial frequency without switching devices. In this method, It makes a sinusoidal wave by widening conduction period using the current resonance in commercial frequency, Hence, the harmonic characteristics can be significantly improved, where the lower order harmonics, such as the fifth and seventh orders are much reduced. The result are confirmed by the theoretical and expermental implementations

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 추계종합학술대회
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• pp.573-576
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• 2000

In this paper, analysis of operating characteristics of hybrid cascade multilevel PWM rectifier without bulky and heavy isolation transformers is presented. The multilevel PWM rectifier is analyzed by using the circuit DQ transformation whereby the static and dynamic characteristics and some useful design relationships are obtained. Then, the operating characteristics such as active/reactive power relationships with respect to control variables, DC voltages build up are presented. It will be shown that the DC voltages for the multilevel output generation may be directly built up from AC utility source. Finally, to confirm the validity of the analysis, MATLAB simulations are tarried out.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.581-585
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• 1998

This paper presents the new current sharing control method of a 12-pulse phase-controlled rectifier(PCR) for a UPS. The control circuit of the 12-Pulse PCR with a parallel operating rectifier system is proposed to balance input currents and to reduce the harmonics of input current. The PCR is used widely in the industrial world, since its cost is much lower than that of the PWM converter and the composition of control circuits is simple. This system is developed and tested for a 3-phase 400KVA UPS system and the experimental results in this application are included.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.39-42
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• 2006

a current stress reduction technique for a boost integrated half-bridge (BIHB) DC/DC converter with voltage doubler type rectifier is proposed for digital car audio amplifier application. In the proposed circuit, two external capacitors are added parallel to the rectifier diodes in the secondary side of the transformer to shape the primary and the secondary current like rectangular waveforms in every switching instance. The experimental results of a 200W industrial sample show that the peak primary current decreases about by 10A. Thus, the proposed technique shows improved high efficiency.