• 전기학회논문지P
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• 제65권2호
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• pp.114-121
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• 2016

This paper is Instant space vector PWM(Pulse Width Modulation)power conversion devices in switching power semiconductors from my generation to losses and switching when the voltage surge and current surge of electronic noise(EMI: Electro Magnetic Interference / RFI: Radio Frequency Interference)to effectively minimize the power soft-switching power conversion circuit topologies of auxiliary resonant DC tank for the purpose of high performance realization of the electric power conversion system by the high-speed switching of a semiconductor device(AQRDCT simultaneously : an active auxiliary resonance using auxiliary Quasi-resonant DC tank)DC link snubber switch has adopted a three-phase voltage inverter. AQRDCL proposed in this paper can reduce the effective and current peak stress of the power semiconductors of the auxiliary resonant snubber circuit compared to the conventional active-resonant DC link snubber, it is not necessary to install the clamp switch of the auxiliary resonant DC link, DC the peak current and power loss of the bus line can be reduced.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1161-1164
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• 1992

In this paper demonstrates the possibiity of utilising clamped mode - series resonant converter technology in the high frequency link inverter configuration. Main circuit of the proposed inverter is analyzed through circuit analys and waveform simulation. In control circuit PLL circuit and 8 bit single chip microcontroller is adopted, therefore flexibility and accuracy of control circuit is increased.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.127-132
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• 2001

In this paper, transmitted sound reduction performance of smart panels is studied according to different piezoelectric materials with piezoelectric shunt damping. Peizo-damping is implemented by using a newly proposed tuning method. This method is based on electrical impedance model and maximizing the dissipated energy at the shunt circuit. By measuring the electrical impedance at the piezoelectric patch bonded on a structure, an equivalent electrical model is constructed near the system resonance frequency. After shunting elements are connected to the equivalent circuit, the shunt parameters are optimally searched based on the criterion of maximizing the dissipated energy at the shunt circuit. Transmitted sound reduction performance is compared according to different piezoelectric materials with peizo-damping. Two piezoelectric materials are selected: PZT-5 and QuickPack IDE actuator. When resonant shunt circuit is considered, the use of PZT-5 exhibited the good sound reduction performance.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권8호
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• pp.455-460
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• 1999

A novel zero-voltage-transition (ZVT) PWM converter for switched reluctance motor (SRM) drives is proposed. A simple auxiliary circuit which consists of one active switch, one resonant inductor, and three diodes provides ZVS condition to all main switches and diodes allowing high frequency operation of the converter with high efficiency. The auxiliary circuit is placed in parallel with the main power flow path and thus it handles only a small fraction of the main power. So, the power rating of the auxiliary circuit can be very small (about 30% of main power). So, the auxiliary circuit can be realized with small power rating and low cost. Operation, features and characteristics of the proposed converter are illustrated and verified on a 1.5 kW, 50 kHz IGBT based (a MOSFET for the auxiliary with) experimental circuit.

• Journal of Power Electronics
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• 제3권4호
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• pp.249-258
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• 2003

This paper presents a high-efficient and cost effective three-phase AC/DC-DC/AC power conversion system with a single two-switch type active Auxiliary Resonant DC Link (ARDCL) snubber circuit, which can minimize the total power dissipation. The active ARDCL snubber circuit is proposed in this paper and its unique features are described. Its operation principle in steady-state is discussed for the three phase AC/DC-DC/AC converter, which is composed of PWM rectifier as power factor correction (PFC) converter, sinewave PWM inverter. In the presented power converter system not only three-phase AC/DC PWM rectifier but also three-phase DC/AC inverter can achieve the stable ZVS commutation for all the power semiconductor devices. It is proved that the proposed three-phase AC/DC-DC/AC converter system is more effective and acceptable than the previous from the cost viewpoint and high efficient consideration. In addition, the proposed two-switch type active auxiliary ARDCL snubber circuit can reduce the peak value of the resonant inductor injection current in order to maximize total system actual efficiency by using the improved DSP based control scheme. Moreover the proposed active auxiliary two-switch ARDCL snubber circuit has the merit so that there is no need to use any sensing devices to detect the voltage and current in the ARDCL sunbber circuit for realizing soft-switching operation. This three-phase AC/DC-DC/AC converter system developed for UPS can achieve the 1.8% higher efficiency and 20dB lower conduction noise than those of the conventional three-phase hard-switching PWM AC/DC-DC/AC converter system. It is proved that actual efficiency of the proposed three-phase AC/DC-DC/AC converter system operating under a condition of soft switching is 88.7% under 10kw output power.

• 한국음향학회지
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• 제30권6호
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• pp.344-352
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• 2011

본 논문에서는 후면추가 탄성체에 의해 고정된 Tonpilz 트랜스듀서의 공진 특성을 등가회로를 이용하여 연구하였다. 후면추가 고정됨으로 인해 발생하는 추가적인 공진특성을 나타낼 수 있는 등가회로를 설계하였으며, 설계된 등가회로를 이용하여 얻은 송신음압감도 (TVR)를 유한요소해석을 통해 도출한 결과와 비교하여 그 타당성을 검증하였다. 등가회로를 이용하여 송신특성을 파악한 결과, 유한요소해석 결과와 일치하였으며, 후면추 고정재료의 강성과 후면추의 질량 변화에 따른 공진 주파수와 송신음압감도 변화를 명확히 파악할 수 있었다. 본 연구에서 도출한 등가회로를 이용하면 설계변수의 변화에 따라 모델을 변경해야하고 긴 계산시간이 요구되는 유한요소해석에 비해 효과적으로 트랜스듀서의 공진특성을 해석할 수 있다.

• 전력전자학회논문지
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• 제26권6호
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• pp.411-420
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• 2021

In this paper, bidirectional LLC-LC resonant DC-DC converter with notch filters in the primary side of resonant circuits is proposed. Even if resonant capacitors are used on the primary and secondary sides, the proposed converter can operate with the high gain characteristics of the LLC resonant converter without mutual coupling of resonant capacitors, regardless of the direction of power flow. In addition, by applying notch filters, the proposed converter can operate with a wider gain control range and can cope with overload and short circuit. The analysis and operating characteristics of the proposed bidirectional LLC-LC resonant converter are investigated. A 3.3 kW prototyped bidirectional LLC-LC resonant converter connected to 750 V_DC buses is designed and tested to verify the validity and applicability of this proposed converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.271-275
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• 2001

In this paper, proposes a novel AC-DC converter of high power factor and high efficiency by partial resonant method. The input current waveform in proposed circuit is got to be a discontinuous sinusoidal form in proportion to magnitude of ac input voltage under the constant duty cycle switching. Thereupon, the input power factor is nearly unity and the control circuit is simple. Also the switching devices in a proposed circuit are operated with soft switching by the partial resonant method. The result is that the switching loss is very low and the efficiency of system is high. The partial resonant circuit makes use of a inductor using step up and $L^2SC$ (Loss-Less Snubber Condenser). The switching control technique of the converter is simplified for switches to drive in constant duty cycle. Some simulative results and experimental results are included to confirm the validity of the analytical results.

• 전기학회논문지
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• 제58권7호
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• pp.1349-1355
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• 2009

This paper is studied on a novel power factor correction (PFC) AC-DC converter of high efficiency by soft switching technique. The input current waveform in the proposed converter is got to be a sinusoidal form composed of many a discontinuous pulse in proportion to the magnitude of a ac input voltage under the constant switching frequency. Therefore, the input power factor is nearly unity and the control method is simple. The proposed converter adding an electric isolation operates with a discontinuous current mode (DCM) of the reactor in order to obtain some merits of simpler control, such as fixed switching frequency, without synchronization control circuit used in continuous current mode (CCM). To achieve the soft switching (ZCS or ZVS) of control devices, the converter is constructed with a new loss-less snubber for a partial resonant circuit. It is that the switching losses are very low and the efficiency of the converter is high, Particularly, the stored energy in a loss-less snubber capacitor recovers into input side and increases input current from a resonant operation. The result is that the input power factor of the proposed converter is higher than that of a conventional PFC converter. This paper deals mainly with the circuit operations, theoretical, simulated and experimental results of the proposed PFC AC-DC converter in comparison with a conventional PFC AC-DC converter.

• 전자공학회논문지S
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• 제35S권9호
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• pp.111-117
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• 1998

본 논문은 LC공진회로를 이용한 사이크로컨버터의 휴지기간 없는 극성절환 방법에 관한 것이다. 제안한 방법에 따르면 극성절환시 회로단락을 방지하기 위한 휴지기간이 요구되지 않는다. 따라서 제어지연 및 출력전류의 고조파성분이 감소하게 된다. 그리고 제안한 방법은 비순환전류형의 다른 자연전류형 사이크로컨버터에도 확장될 수 있다. 본 논문에서는 휴지기간 없는 극성절환의 스위칭 방법에 대하여 검토하였으며 제안한 방법의 유용성을 확인하기 위하여 LC공진회로를 이용한 사이크로콘버터에 적용실험을 수행하였다.