Three-Phase <i>LLC</i> Battery Charger: Wide Regulation and Improved Light-Load Operation

Arshadi, Sayed Abbas; Ordonez, Martin; Eberle, Wilson; Craciun, Marian; Botting, Chris

doi:10.1109/tpel.2020.3006422

Cited by 49 publications

(11 citation statements)

References 33 publications

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“…The interested three-phase LLC resonant converter consists of three half-bridge DC-AC inverter modules, three resonant modules and three single-phase transformers connected in floated star point at primary side. This structure has been shown many advantages due to the inherent current-balancing characteristics between the phases ([23]- [25]). On the secondary side of the transformer are three half-bridge rectifier modules.…”

Section: Current Sharingmentioning

confidence: 99%

Unbalanced three-phase interleaved LLC resonant converter: current phase angle balancing technique

Thong

Linh

Canh

et al. 2022

IJPEDS

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Resonant power supplies have the advantage over traditional pulse width modulation (PWM) converters due to their soft switching capabilities. In addition, the output current ripple can be reduced by using three phase interleaving structure. However, this structure also suffers from some disadvantages, such as resonant current imbalance. Most previous solutions have been focused on hardware as adding extra power switches, increasing the cost and volume of the converter. There are not many software solutions due to the difficulty in modeling unbalance three-phase. This paper will propose a smoothly resonant current balancing solution for the three-phase interleaved LLC structure which is based on controlling directly resonant current phase angles (CPAB). This proposed method shows better current balance and response than the old trigonometric current balancing (TCB) method. The proposed technique is also verified by a 48 V 3.6 kW prototype converter and its experimental results.

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Section: Current Sharingmentioning

confidence: 99%

Unbalanced three-phase interleaved LLC resonant converter: current phase angle balancing technique

Thong

Linh

Canh

et al. 2022

IJPEDS

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“…Nowadays, the applications of photovoltaic generation, new energy electric vehicles, high power charging piles and energy storage systems are developing very rapidly, which has significantly increased the demand for DC–DC isolated converters. Because of the high efficiency, wide range of zero voltage switching (ZVS) and electrical isolation, LLC resonant converter has been widely used (Arshadi et al , 2021; Wang et al , 2019; Kim, 2020; Feng and Lee, 2014; Kim et al , 2020; Fei et al , 2018).…”

Section: Introductionmentioning

confidence: 99%

Parameters optimization design method for LLC resonant converter based on impedance model

Yao

Han

Liao

et al. 2022

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Purpose This paper aims to better design the resonant tank parameters for LLC resonant converter. And, it is found that under heavy load, the voltage gain is affected by junction capacitors of the primary side switching and the parasitic parameters of the secondary side diodes converted to the primary side, which will cause the voltage gain decreased when the switching frequency decreased. Design/methodology/approach This paper proposes an optimization parameters design method to solve this problem, which was based on impedance model considering the parasitic parameters of switching devices and diodes. Findings The effectiveness of the proposed method is verified by impedance Bode plots and experimental results. Originality/value From the perspective of impedance modeling, this paper finds the reasons for the insufficient voltage regulation capability of LLC resonant converters under heavy load and finds solutions through analysis.

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“…The three-phase LLC improves power level further while still maintaining the benefits, such as zero-voltage switching and high efficiency, and also improves disadvantages, such as a high output ripple current and unbalanced current. In addition, different transformer connection methods can lead to different circuit characteristics [9][10][11]. In general, the three-phase LLC has two types of transformer connections: one is Y-connection, and the other is ∆-connection.…”

Section: Introductionmentioning

confidence: 99%

Analysis and Design of Three-Phase LLC Resonant Converter with Matrix Transformers

et al. 2022

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This study presents the topology of a three-phase LLC resonant converter with matrix transformers. The three-phase LLC resonant converter has the advantages of conventional LLC resonant converters, including zero-voltage switching at the primary side, zero-current switching at the secondary side, high-frequency feasibility, and high efficiency. Moreover, it has additional advantages that differ from conventional LLC, including low output capacitor current ripple, natural current sharing in three resonant currents, and a high power level. As a result of the above mentioned characteristics, LLC topology has been used in many electric vehicle charging systems, server power systems, and other high-power applications. However, as the power level becomes higher and higher, the input voltage is usually too high to reduce conduction loss, and the output current also increases. This situation makes transformer design more difficult. The increasing current means more core and copper loss, and the heat dissipation of the transformer becomes more difficult. Matrix transformer technology can improve this problem directly and simply. By utilizing matrix transformers, which are primary series connected and secondary parallel connected, the primary voltage stress and secondary current stress of the transformers can be reduced, and the output current can be distributed. The analysis of the proposed converter in this study includes a circuit operation introduction, a time-domain analysis, calculation of the transfer ratio curve in the frequency domain, and a loss analysis. The theoretical analysis and performance of the proposed converter are verified. A three-phase LLC resonant converter with matrix transformers prototype is built with a high input voltage of 800-VDC and high output current of 200-A. The output voltage is 100-VDC. The waveform and efficiency data will be shown in the experimental results.

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Three-Phase LLC Battery Charger: Wide Regulation and Improved Light-Load Operation

Cited by 49 publications

References 33 publications

Unbalanced three-phase interleaved LLC resonant converter: current phase angle balancing technique

Unbalanced three-phase interleaved LLC resonant converter: current phase angle balancing technique

Parameters optimization design method for LLC resonant converter based on impedance model

Analysis and Design of Three-Phase LLC Resonant Converter with Matrix Transformers

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