• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.151-152
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• 2011

This paper describes a cross-regulation characteristics of a multi-output LLC resonant converter widely used in consumer electronics. The output characteristics of the multi-output LLC converter is derived from the assumption that the current and voltage to flow through the resonant network is sinusoidal and the duty loss is investigated. The simulation results are provided to verify the theoretic results.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권2호
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• pp.94-97
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• 2007

The desin and implementation of a CMOS analog integrated circuit that provides dual-mode modulations, PWM for active clamp reset converter and PFM for LLC resonant converter, is described. The proposed controller is capable of implementing programmable soft start and current-mode control with compensating ramp for PWM and frequency shifting soft start for PFM. Also it provides delay time for both modes. PWM mode is implemented by active clamp reset converter and PFM mode is implemented by LLC resonant convereter, respectively. The chip is fabricated using the 0.6um high voltage CMOS process.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.365-366
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• 2017

LLC resonant DC-DC converter is widely used in many kinds of applications such as battery energy storage systems, wireless power transfer and high voltage power supply. It is because of characteristics like high efficiency, power density, isolation, wide power level and stability enhancement at high switching frequency. Small signal modeling helps to design controller of the converter by approximating the behavior of nonlinear system with linear state equations. This paper presents comparison between small signal modeling analysis and experimental results of LLC resonant converter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.825-829
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• 1993

By using the state plane approach, the steady state analysis and desing of a high frequency LLC-type series resonant converter and LLC-type parallel resonant converter operating in the continuous conduction mode is presented. When a LLC-type P.R.C operates above resonant frequency, the switching transitor can be turn off at zero voltage. A set of characteristic frequency are plotted from which desing parameters can be obtained.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.15-16
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• 2016

This paper proposes an isolated DCDC converter that consists of unregulated LLC resonant converter and non-isolated synchronous buck converter for battery charger of energy storage systems application. The unregulated converter operates as transformer with fixed duty ratio and switching frequency. The synchronous buck converter is installed in the output of the LLC resonant converter. And the converter charges and discharges the battery by controlling a current of battery. The proposed converter can get the high efficiency by separating function. This paper explains design of an unregulated converter and synchronous converter.

• 전력전자학회논문지
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• 제24권4호
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• pp.294-302
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• 2019

A capacitor common connected LLC resonant converter with auxiliary switches for a wide output voltage control range is presented in this paper. The proposed converter can be controlled in two ways to achieve a wide output voltage control range of Vo-3Vo. The first control method is performed through pulse width modulation of the auxiliary switches and primary switching devices. The second control method is conducted through frequency modulation of the primary switching devices configured to operate in full-bridge switching modes, when the auxiliary switches are turned off. The feasibility of the proposed converter is verified by the experimental results of a 5 kW prototype.

• 한국융합학회논문지
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• 제8권11호
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• pp.313-319
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• 2017

본 논문에서는 전기자동차의 핵심부품인 DC-DC 컨버터를 LLC공진형 컨버터에 신소재(Ga-N HEMT)를 이용하여 설계함으로써 소형화가 가능하며, 공진주파수를 자유롭게 변경할 수 있으며, 2차측 출력부에 SR Topology를 추가하여 전원장치의 동작 시 효율 및 온도특성을 개선하는 설계기법을 제안하였다. 이를 통해 고효율과 소형화를 얻을 수 있도록 회로를 구성하였으며, 제안된 컨버터는 200[kHz]의 높은 스위칭주파수를 가지고 동작시키게 됨으로써 스위칭주파수의 변화 및 회로구현의 장점과 스위칭주파수의 극대화로 인해서 LLC 및 PFC의 사이즈를 40[%] 최소화 할 수 있었으며, 동작온도의 특성이 250W(12V/20A)에서 온도를 측정한 결과 방열판 없이 $60{\sim}65^{\circ}C$를 나타냄을 확인하였다. 이러한 설계결과를 토대로 향후 1[kW]이상까지 구현하고자 한다.

• 전력전자학회논문지
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• 제13권6호
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• pp.453-460
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• 2008

본 논문은 중용량에 적합한 새로운 이중출력 LLC 공진형 DC/DC 컨버터에 관한 것으로써, 별도의 Post-regulator및 추가되는 제어 IC 없이 정밀한 이중출력이 가능한 새로운 방식의 컨버터를 제안한다. 제안된 컨버터의 제어방식은 펄스폭 변조(PWM)와 동시에 주파수 변조(PFM)를 통해 이루어지며 Master 와 Slave 출력을 각각 주파수, 듀티로 제어함으로써 Slave 출력을 위한 별도의 Post-Regulator 및 제어 IC가 필요 없기 때문에, 저가의 컨버터 구현이 가능하다. 또한 기존 LLC 공진형 DC/DC 컨버터와 같이 스위칭 소자의 영전압 스위칭이 보장되는 동시에, Post-Regulator 로 인한 손실이 없기 때문에 효율 및 발열 특성이 매우 우수하다. 본 논문에서는 제안된 컨버터의 우수성과 신뢰성 검증을 위해, 실제로 50" FHD급 PDP용 전원회로를 위한 시뮬레이션 검토 및 시작품을 제작하고 이를 이용한 실험결과를 바탕으로 제안된 컨버터의 타당성을 검증한다.

• 전력전자학회논문지
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• 제24권6호
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• pp.438-444
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• 2019

In this paper, bidirectional LLC resonant DC/DC converters with the primary auxiliary windings in transformers of resonant circuits are proposed. Although the resonant capacitors are used on both the primary and secondary sides, regardless of the direction of power flow, the main feature of the proposed converters exhibits high gain characteristics without any mutual coupling between the resonant capacitors. For one of the proposed converters, an investigation of the operating characteristics in each mode has been carried out. A prototype of a 3.3 kW bidirectional LLC resonant converter for interfacing 750 V DC buses has been built and tested to verify the validity and applicability of the proposed converter.

• Journal of Power Electronics
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• 제14권1호
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• pp.40-47
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• 2014

An average current mode control scheme that consistently offers good dynamic performance for LLC series resonant DC-to-DC converters irrespective of the changes in the operational conditions is presented in this paper. The proposed control scheme employs current feedback from the resonant tank circuit through an integrator-type compensation amplifier to improve the dynamic performance and enhance the noise immunity and reliability of the feedback controller. Design guidelines are provided for both current feedback and voltage feedback compensation. The performance of the new control scheme is demonstrated through an experimental 150 W converter operating with 340 V to 390 V input voltage to provide a 24 V output voltage.