LLC resonant converter controller with novel light load control

Yang, Chun-Hsu; Liang, Tsorng–Juu; Chen, Kai–Hui; Li, Ji-Shiuan; Lee, Ji-Shiang

doi:10.1109/peac.2014.7037842

Cited by 12 publications

(3 citation statements)

References 12 publications

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“…However, a complex CLC filter structure is required to reduce the output voltage ripple, which increases the cost and size of converter. The modified burst-mode control presented in [16] can ensure constant output voltage ripple by decreasing the switching frequency gradually during burst-on time. However, the output ripple ratio is still large under burst mode.…”

Section: Introductionmentioning

confidence: 99%

Study on Wide Dimming Range Solution for LLC LED Driver Based on an Accurate Time-Domain Analysis Considering the Parasitical Components

Xie

Chen

et al. 2022

IEEE Access

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To achieve ultra-deep dimming ratio in LED driver application, the resonant process of LLC resonant converter considering the critical parasitic components has been analyzed in detail with time-domain solution in this paper. The effects of three parasitic components, including the equivalent parasitic capacitor Cp in parallel with the transformer, the equivalent output capacitor Ca of the bridge switches and the parasitic capacitor CL of resonant inductor, on the resonant current during the dead-time and switching frequency under light-load condition have been taken account. Brief equivalent circuits during the resonant process of LLC resonant converter and corresponding mathematical functions based on time-domain analysis are presented. After that, accurate frequency curve of the converter and required dead-time in variation with output current have been calculated out.Theoretical analysis show that the LLC resonant converter can achieve ultra-low dimming ratio without entering the burst mode with appropriate external capacitor in parallel with the output of the bridge and zero voltage switching (ZVS) of switches by self-adjusting the dead-time. Finally, an experimental prototype has been built up to verify the theoretical analysis and 0.5% LED dimming ratio has been achieved. The theoretical analysis results meet the experimental results very well, which demonstrates that the time-domain solution presented in this paper can achieved very high accuracy. INDEX TERMSLLC resonant converter, Light-emitting diode (LED) driver, wide dimming range, parasitic components, time-domain analysis. NOMENCLATURE VFMvariable frequency modulation Vo -output voltage Io -output current Lr -resonant inductor Cr -resonant capacitor N -turns ratio of transformer Q1upper arm switch of bridge Q2upper arm switch of bridge Cossoutput capacitor of switch Q1 or Q2 Cd -junction capacitor of a secondary side rectifier Ctf -parasitic capacitor of the transformer on the primary side CL -parasitic capacitor of the resonant inductor Lr Cp -equivalent parasitic capacitor in parallel with the primary winding of the transformer Ca -equivalent output capacitor of bridge switches Ce -external capacitor in parallel between the midpoint of bridge and primary ground vgH and vgL -driving signals of primary switches; ir -resonant current im -magnetizing current of transformer vcr -voltage across resonant capacitor Cr

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Section: Introductionmentioning

confidence: 99%

Study on Wide Dimming Range Solution for LLC LED Driver Based on an Accurate Time-Domain Analysis Considering the Parasitical Components

Xie

Chen

et al. 2022

IEEE Access

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“…Low-load condition occurs with the decrease in battery charging current. Low or light loading is detected by measurement of average input current or monitoring the control signal voltage [27,28]. Decision of the control method type is handled accordingly.…”

Section: Introductionmentioning

confidence: 99%

“…Burst mode or DOM is one of the most convenient operation methods of DC/DC converters and there are several pieces of research about burst mode operation [28]. Ontime and off-time optimization studies are important to observe the output voltage and current of the converter [33,34].…”

Section: Introductionmentioning

confidence: 99%

Smart Efficiency Tracking for Novel Switch—LLC Converter for Battery Charging Applications

Çalışkan

Üstün

2022

Energies

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In this study, a novel smart efficiency tracking (SET) algorithm for GaN-based LLC resonant converter for quick battery charging of light electric vehicles is proposed. Conventional frequency modulation (FM) method, single pulse width modulation method (S-PWM) and discontinuous operation mode method (DOM) are used to track the converter efficiency which varies for different loading conditions during the battery charging process. First, the charging modes are explained to define the efficiency variation clearly. Then, the theoretical background of GaN-based LLC resonant converter is presented and the details of design study are given. Third, the principles of three different switching control strategies, the modeling study and the simulation results are put forward. Finally, the details of the implementation of three different switching strategies are presented for the validation of the study. Furthermore, the implementation of the design and its impact on battery charging are discussed. The proposed efficiency tracking method is validated with a 20% efficiency increase for the low loading conditions of GaN-based LLC converter.

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Predictive charge control for LLC resonant converters

Chen

Lei

et al. 2022

J. Power Electron.

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LLC resonant converter controller with novel light load control

Cited by 12 publications

References 12 publications

Study on Wide Dimming Range Solution for LLC LED Driver Based on an Accurate Time-Domain Analysis Considering the Parasitical Components

Study on Wide Dimming Range Solution for LLC LED Driver Based on an Accurate Time-Domain Analysis Considering the Parasitical Components

Smart Efficiency Tracking for Novel Switch—LLC Converter for Battery Charging Applications

Predictive charge control for LLC resonant converters

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