Analysis on Load-Adaptive Phase-Shift Control for High Efficiency Full-Bridge LLC Resonant Converter Under Light-Load Conditions

Recently, the full-bridge (FB) LLC resonant converter is getting more attention due to its zero-voltage switching of the primary switches, zero-current switching of rectifier diodes, and high power capability. However, the conversion efficiency is degraded under light-load conditions due to the core loss in magnetic components and the switching loss in semiconductor devices. In this paper, a new control method is proposed for the FB LLC resonant converter. In the proposed method, the frequency control is basically used to regulate the output voltage over entire load conditions. Moreover, the proposed method utilizes phase-shifted gate signals between switch legs, based on predetermined optimal duty ratio under light-load conditions. At this point, the optimal duty ratio is determined to get minimum power loss under each light-load condition through the loss analysis of all components. Therefore, the proposed method makes high efficiency under light-load conditions. To confirm the validity of this paper, the prototype of the network power supply with 320-385 V dc input and 48 V/720 W dc output is tested.

[1]  Gun-Woo Moon,et al.  Analysis for LLC resonant converter considering parasitic components at very light load condition , 2011, 8th International Conference on Power Electronics - ECCE Asia.

[2]  W. Fu,et al.  A dynamic core loss model for soft ferromagnetic and power ferrite materials in transient finite element analysis , 2004, IEEE Transactions on Magnetics.

[3]  Milan M. Jovanovic,et al.  Light-Load Efficiency Optimization Method , 2009, 2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition.

[4]  J.A. Abu-Qahouq,et al.  Analysis and Design of Voltage Regulator With Adaptive FET Modulation Scheme and Improved Efficiency , 2008, IEEE Transactions on Power Electronics.

[5]  Yan-Fei Liu,et al.  A new resonant gate drive circuit with efficient energy recovery and low conduction loss , 2008, 31st Annual Conference of IEEE Industrial Electronics Society, 2005. IECON 2005..

[6]  Toshihisa Shimizu,et al.  Loss Reduction of Laminated Core Inductor used in On-board Charger for EVs , 2015 .

[7]  T.H. Lee,et al.  A constant-frequency method for improving light-load efficiency in synchronous buck converters , 2005, IEEE Power Electronics Letters.

[8]  Yan Liang,et al.  Optimal design methodology for LLC resonant converter , 2006, Twenty-First Annual IEEE Applied Power Electronics Conference and Exposition, 2006. APEC '06..

[9]  F.C. Lee,et al.  Power architecture design with improved system efficiency, EMI and power density , 2008, 2008 IEEE Power Electronics Specialists Conference.

[10]  K. J. Tseng,et al.  Effects of multi-segment structure in core loss reduction of MnZn ferrite , 2000, Proceedings IPEMC 2000. Third International Power Electronics and Motion Control Conference (IEEE Cat. No.00EX435).

[11]  Roman Kolano,et al.  Reduction of Power Losses in the Tape-Wound FeNiCuNbSiB Nanocrystalline Cores Using Interlaminar Insulation , 2014, IEEE Transactions on Magnetics.

[12]  Paolo Mattavelli,et al.  Digital implementation of driving scheme for synchronous rectification in LLC resonant converter , 2010, 2010 IEEE Energy Conversion Congress and Exposition.

[13]  Gun-Woo Moon,et al.  A Half-Bridge LLC Resonant Converter Adopting Boost PWM Control Scheme for Hold-Up State Operation , 2014, IEEE Transactions on Power Electronics.

[14]  Jae-Hyun Kim,et al.  A Novel Accurate Primary-Side Control (PSC) Method for Half-Bridge (HB) LLC Converter , 2015, IEEE Transactions on Power Electronics.

[15]  Sheng Ye,et al.  A New Dual-Channel Resonant Gate Drive Circuit for Low Gate Drive Loss and Low Switching Loss , 2008, IEEE Transactions on Power Electronics.

[16]  Jae-Hyun Kim,et al.  Load Adaptive Gate Driving Method for High Efficiency Under Light-Load Conditions , 2014, IEEE Transactions on Industrial Electronics.

[17]  Jianping Ying,et al.  Analysis and Implementation of LLC Burst Mode for Light Load Efficiency Improvement , 2009, 2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition.

[18]  Jun-Young Lee,et al.  An Isolated DC/DC Converter Using High-Frequency Unregulated $LLC$ Resonant Converter for Fuel Cell Applications , 2011, IEEE Transactions on Industrial Electronics.

[19]  Sheng Ye,et al.  A New Resonant Gate Drive Circuit for Synchronous Buck Converter , 2007, IEEE Transactions on Power Electronics.

[20]  Yen-Shin Lai,et al.  Switching Control Technique of Phase-Shift-Controlled Full-Bridge Converter to Improve Efficiency Under Light-Load and Standby Conditions Without Additional Auxiliary Components , 2010, IEEE Transactions on Power Electronics.

[21]  Jian-Min Wang,et al.  A Novel Control Scheme of Synchronous Buck Converter for ZVS in Light-Load Condition , 2011, IEEE Transactions on Power Electronics.

[22]  Gun-Woo Moon,et al.  A novel accurate primary side control (PSC) method for half-bridge (HB) LLC converter , 2014, 2014 International Power Electronics Conference (IPEC-Hiroshima 2014 - ECCE ASIA).

[23]  Alfred Rufer,et al.  Global Loss Evaluation Methods for Nonsinusoidally Fed Medium-Frequency Power Transformers , 2009, IEEE Transactions on Industrial Electronics.

[24]  Charles R. Sullivan,et al.  Accurate prediction of ferrite core loss with nonsinusoidal waveforms using only Steinmetz parameters , 2002, 2002 IEEE Workshop on Computers in Power Electronics, 2002. Proceedings..

[25]  Yu-Kang Lo,et al.  Phase-Shifted Full-Bridge Series-Resonant DC-DC Converters for Wide Load Variations , 2011, IEEE Transactions on Industrial Electronics.

[26]  Gun-Woo Moon,et al.  Asymmetric PWM Control Scheme During Hold-Up Time for $LLC$ Resonant Converter , 2012, IEEE Transactions on Industrial Electronics.

[27]  Fan Wang,et al.  LLC performance enhancements with frequency and phase shift modulation control , 2014, 2014 IEEE Applied Power Electronics Conference and Exposition - APEC 2014.

[28]  Jong-Woo Kim,et al.  A Simple Switching Control Technique for Improving Light Load Efficiency in a Phase-Shifted Full-Bridge Converter with a Server Power System , 2014, IEEE Transactions on Power Electronics.

[29]  Milan M. Jovanovic,et al.  Methods of reducing audible noise caused by magnetic components in variable-frequency-controlled switch-mode converters , 2011, APEC 2011.