A High Efficiency LLC Resonant Converter with Wide Ranged Output Voltage Using Adaptive Turn Ratio Scheme for a Li-Ion Battery Charger

Han, Hua; Choi, Yeong-Jun; See-Yong, Choi; Kim, Rae-Yong

doi:10.1109/vppc.2016.7791570

Cited by 16 publications

(3 citation statements)

References 11 publications

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“…This causes a sharp reduction in the converter efficiency. Thereby, these LLC resonant converters always have a trade-off relationship between output voltage and conversion efficiency and thus have limited potential for use in applications requiring a wide output voltage [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

A Novel Dual Integrated LLC Resonant Converter Using Various Switching Patterns for a Wide Output Voltage Range Battery Charger

et al. 2019

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This paper proposes a novel dual integrated LLC resonant converter (DI-LRC) with a wide output voltage range using various switching patterns. The primary side of the proposed DI-LLC converter consists of two resonant tanks and six switches, while the secondary side consists of a six-pulse diode rectifier. Depending on the switching pattern of the primary switch, the DI-LRC converter is performed by single full-bridge operation with a voltage gain of 1, series-connected full-bridge operation with a voltage gain of 0.5, series-connected half bridge operation with a voltage gain of 0.25, and parallel-connected full-bridge operation with a voltage gain of 2. Accordingly, the proposed DI-LRC converter has four voltage gain curves with different variations and achieves a wider output voltage range than the conventional single voltage gain curve in a given operating frequency range. In this paper, the equivalent circuits derived for each switching pattern are proposed to analyze the operating characteristics of the proposed converter according to each switching pattern, and each Q factor and voltage gain are calculated based on the analyzed equivalent circuit. The performance of the proposed converter and switching pattern is verified using the simulation and experimental results of the prototype battery charger, which is designed to be 4-kW class.

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Section: Introductionmentioning

confidence: 99%

A Novel Dual Integrated LLC Resonant Converter Using Various Switching Patterns for a Wide Output Voltage Range Battery Charger

et al. 2019

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“…Thus, resonant converters are the key technology in DC power applications [1]. Consequently, many resonant converter topologies have been widely used as battery chargers, especially for EVs [7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Constant frequency operation of parallel resonant converter for constant-current constant-voltage battery charger applications

Gücin

Biberoğlu

Fincan

2018

J. Mod. Power Syst. Clean Energy

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This paper proposes a design and control approach to parallel resonant converter (PRC) based battery chargers. The proposed approach is particularly suitable for the constant-current constant-voltage (CC-CV) charging method, which is the most commonly utilized one. Since the PRC is operated at two different frequencies for each CC and CV charging modes, this approach eliminates the need for complicated control techniques such as the frequency-control and phase-shift-control. The proposed method not only simplifies the design and implementation processes of the converter unit but also simplifies the design of output filter configuration and decreases the number of the required components for the control of the charger. The proposed method is confirmed by two experimental setups. The results show that the designed charger circuit ensured a very stable constant current in CC charging phase, where the charging current is fixed to 1.75 A. Although a voltage increase in CV phase is observed, the charger circuit is able to decrease the charging current to 0.5 A in CV phase, as depicted in battery data-sheet. The efficiency of the charger is figured out to be in the range of 86%-93% in the first setup, while it is found to be in the range of 78%-88% in the second setup, where a high frequency transformer is employed.

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“…In [8][9][10], the k is increased to reduce the operation loss of the converter and improve the working efficiency, but it will cause the change range of the switching frequency to increase at light load, which is not conducive to the integrated design of magnetic components and the improvement of power density. In [11,12], auxiliary circuits have been added to improve efficiency at light loads, but this method changes the circuit structure and affects the stability of the circuit to some extent.…”

Section: Introductionmentioning

confidence: 99%

Self‐adaptation load change control strategy for three‐phase staggered parallel LLC resonant converter

Feng

Manman

Yuanyuan

et al. 2018

IET Power Electronics

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The resonant frequency of LLC resonant converter has a wide range of switching frequency due to load changes and it easily enters high frequency band during light load and no-load conditions. Therefore, this study proposes a self-adaptation load change control strategy. According to different load conditions, the converter automatically selects the best control mode among three control methods, which are pulse-frequency modulation, symmetrical pulse-width modulation and burst. By fully utilising the characteristics of the load-independent point in the gain curve and the relationship between the resonant current and the load, the switching conditions between the control strategies are further designed and optimised. In addition, based on the adaptive load change control strategy, the design value of k (the ratio of the excitation inductor to the resonant inductance of the transformer) is increased, which solved the disadvantage of large change of the switch range. And the converter can not only effectively control the output voltage during light load, but also works in the soft-switching state, which can improve the working efficiency of the converter to above 91%. Finally, taking a three-phase staggered parallel LLC resonant converter as the research object, an experimental prototype was developed based on SiC devices to verify the correctness and rationality of the proposed control strategy.

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A High Efficiency LLC Resonant Converter with Wide Ranged Output Voltage Using Adaptive Turn Ratio Scheme for a Li-Ion Battery Charger

Cited by 16 publications

References 11 publications

A Novel Dual Integrated LLC Resonant Converter Using Various Switching Patterns for a Wide Output Voltage Range Battery Charger

A Novel Dual Integrated LLC Resonant Converter Using Various Switching Patterns for a Wide Output Voltage Range Battery Charger

Constant frequency operation of parallel resonant converter for constant-current constant-voltage battery charger applications

Self‐adaptation load change control strategy for three‐phase staggered parallel LLC resonant converter

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