• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.6
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• pp.627-637
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• 2011

To cope with the high power density and low cost in switching power supply, this paper presents a novel planar transformer, which can regulate the leakage inductance of planar transformer used for LLC resonant converter. Modeling and analysis of a novel planar transformer are discussed in detail and a prototype 200W LLC resonant converter is tested to verify.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.3
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• pp.177-187
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• 2009

This paper describes the gain characteristics of Multi-output LLC series resonant converter by using the new analytical method. Specially, using the Math-CAD simulated result, this paper analyzes an influence from the secondary leakage inductance of transformer. The theoretical results are verified through an experimental prototype of the 430W 3-output LLC resonant converter for 46inch PDP power module.

• Journal of Power Electronics
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• v.13 no.1
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• pp.1-8
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• 2013

This paper presents a resonant non-inverting buck-boost converter in which all switches operate under ZCS conditions. In a symmetric configuration, a CLL resonant tank along with an inverter arm and a rectifying diode are employed. The diode is turned off at ZCS and hence the problem of its reverse recovery is obviated also. As a result switching losses and EMI are reduced and switching frequency can be increased. The converter can work at DCM and CCM depend on the switching frequency and the load-current. Experimental results from a 200W/200KHz laboratory prototype verify operation of the proposed converter and the presented theoretical analysis.

• Proceedings of the KIEE Conference
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• summer
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• pp.1166-1168
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• 2004

The high frequency series resonant converter has been widely used for the non-contact power supply system with the large air gap and the increased leakage inductance of the non-contact transformer. However. the high frequency series resonant converter has the disadvantages of high voltage gain characteristics in the overall load range due to the large air gap and the circulating magnetizing current. In this paper, unit voltage gain is revealed in the proposed three-level series-parallel resonant converter. The results are verified on the simulation results and the 5kW experimental prototype.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.5
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• pp.397-405
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• 2009

Nowadays, power supplies for LCD TV of larger and slimmer screen size are required to have high power density and high efficient characteristics. In order to meet these requirements, Multi-phase interleaved LLC resonant converter is applied for increasing power density and reducing the current rating in the used devices. In this paper, gain characteristics and the experimental results of the proposed two-phase LLC resonant converter which implemented by the simple control circuit are verified based on the theoretical analysis and the 300W experimental prototype.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.424-427
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• 2007

The LLC series resonant converter with a LLT (Inductor-Inductor-Transformer) transformer for PDP power supply is presented. LLT transformer used to combine the inductor and transformer into one unit has the increased leakage inductance in the primary and secondary due to the winding method and the use of the gaped core. The increased leakage inductance in the primary and secondary of LLT transformer can be impacted on the DC voltage gain characteristics of LLC series resonant converter. In this paper, DC gain characteristics and the experimental results of the LLC series resonant converter with a LLT transformer are verified on the Math-CAD simulation based on the theoretical analysis and the 600W experimental prototype.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.522-523
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• 2012

In this paper, we present an experimental results of 15kV class high-volatge power supply using the LLC resonant half-bridge converter for CNT lamp. The resonant current of the LLC resonant half-bridge converter prototype in the steady state was stable. The output voltage of prototype converter was maintained at about 15kV in the steady state.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.188-189
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• 2010

This paper proposed a new zero-voltage switching(ZVS) Two-Inductor boost converter. The conventional Two-Inductor boost converter has defect. When the switch is turned off, the high voltage spike is occurred in the switch by leakage inductance and switch parasitic capacitor. To solve this problem, the parallel resonant capacitor is added to the conventional Two-Inductor boost converter. Using quasi-resonant between parallel resonant capacitance and leakage inductance, the switches is operated soft switching. A reduction of transformer turn ratio is achieved by the voltage doubler rectifier.

• Journal of Power Electronics
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• v.17 no.4
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• pp.860-873
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• 2017

The present article reports an analysis and investigation of a direct AC-AC quasi-resonant converter. A bidirectional power device, whose switching frequency is lower than the frequency of the current passing through the load, is used for its realization. The zero voltage switching mode is described when zero voltage on the power device is available by measuring it with the control system. The continuous current in the resonant inductance by switching the power device at zero voltage is considered, and it is characterized by two sub-modes. A mathematical analysis of the processes has been made and comparative results from the computer simulation and experimental study have been brought. The converter can be used in a wide areas of power electronics: induction heating, wireless power transfer, AC-DC converters, etc.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.1
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• pp.46-52
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• 2021

This study proposes a feedforward compensation control method to reduce 120 Hz output voltage ripple in a single-phase AC/DC rectifier system composed of PFC and LLC resonant converters. The proposed method compensates for the voltage ripple of the DC-link by using the AC input and DC output power difference, and then reduces the final output voltage ripple component of 120 Hz through feedforward compensation based on the linearized frequency gain curve of the LLC resonant converter. Through simulation and experimental results, the validity of the ripple reduction performance was verified by comparing the conventional PI controller and the proposed feedforward compensation method.