LLC Resonant Converter With Matrix Transformer

Huang, Daocheng; Ji, Shu; Lee, Fred C.

doi:10.1109/tpel.2013.2292676

Cited by 210 publications

(41 citation statements)

References 17 publications

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“…Moreover, the terminations are still placed outside the windings which creating the same problem as [21]. In [24], [25], and [26] the integration concept is revisited and improved for low profile PCB-winding design. In [23], the "integration" means integrating SRs and capacitors inside each PCB layer, so that the termination loop is reduced and via connections can be removed.…”

Section: Chapter 3 Transformer Design: Terminations and Viasmentioning

confidence: 99%

Optimal Design of Megahertz $LLC$ Converter for 48-V Bus Converter Application

Cai

Ahmed

et al. 2020

IEEE J. Emerg. Sel. Topics Power Electron.

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The intermediate bus architecture employing the 48V bus converter is one of the most popular power architecture. 48V to 12V bus converter has wide applications in telecommunications, networks, aerospace, and military, etc. However, today's state of the art products has low power rating or power density and becomes difficult to satisfy the demand of increasing power of the loads. To improve the current design, a GaN (Gallium Nitride) based two-stage solution is proposed for the bus converter. The first stage Buck converter regulates the 40V to 60V variable input to a fixed 36V bus voltage. The second stage LLC converter convert the 36V to 12V by a 3:1 transformer. The whole solution achieves the fixed frequency control. The thesis focus on the detail design and optimization of LLC converter, especially its transformer. To have high density and high efficiency, the transformer design becomes critical at MHz frequency. The matrix transformer concept is applied and a merged winding structure is used for flux cancellation, which effectively reduces the AC winding losses. A new fully interleaved termination and via design is proposed. It achieves significant reduction in loss and leakage flux. In addition, to study the current sharing of parallel winding layers, a 1-D analytic model is proposed and a symmetrical winding layer scheme is used to balance the current distribution. The hardware is built and tested. The proposed two-stage converter achieves the best performance compared to the current market. Intermediate bus architecture (IBA) has wide applications in telecommunication, server and computing, and military power supplies. The intermediate bus converter (IBC) is the key stage in the IBA, where the DC bus voltage from the front-end power supply is converted to a lower intermediate bus voltage. Traditional IBC suffers from bulky magnetic components including inductors and transformers.This work illustrates the design and implementation of a two-stage IBC, where the firststage Buck converter will provide regulation and the second stage LLC converter will provide isolation. Thanks to the soft-switching capability of LLC, the magnetic volume can be significantly reduced by raising the switching frequency of the converter. Therefore, planar magnetics can be used and placed directly inside of the printing circuit board (PCB), which allows for higher power densities and easy manufacturing of the magnetics and overall converter. However, as the frequency goes higher, the AC losses of the transformer caused by the eddy current, skin effect, and proximity effect become dominant. As a result, high-frequency transformer design becomes the key for the converter design. First, matrix transformer concept is applied to distribute the high current and reduce the conduction loss. Second, a novel merged winding structure is proposed for better transformer winding interleaving. Third, a new terminal structure of the transformer is proposed. Finally, the current sharing between parallel windings are modeled and studied. All the eff...

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Section: Chapter 3 Transformer Design: Terminations and Viasmentioning

confidence: 99%

Optimal Design of Megahertz $LLC$ Converter for 48-V Bus Converter Application

Cai

Ahmed

et al. 2020

IEEE J. Emerg. Sel. Topics Power Electron.

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“…The 500kHz LLC hardware is designed based on Matrix Transformer for LLC Resonant Converters [18]. In paper [18], the LLC converter was a 1MHz 1kW 390V/12V unregulated DCX with GaN devices. Here the LLC converter is 500kHz 1kW 390V/12V regulated DC/DC converter with Si devices.…”

Section: Experimenal Verificationmentioning

confidence: 99%

“…With the fast development of wideband gap devices and novel magnetic materials [15][16] [17], the trend of push switching frequency higher continues. And MHz LLC converters with GaN devices are designed for different applications [18] [19].…”

Section: Introductionmentioning

confidence: 99%

Soft start-up for high frequency LLC resonant converter with optimal trajectory control

Chao

Lee

2015

2015 IEEE Applied Power Electronics Conference and Exposition (APEC)

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this paper investigates the soft start-up for high frequency LLC resonant converter with optimal trajectory control. Two methods are proposed to realize soft start-up for high frequency LLC converter by commercial low-cost microcontrollers (MCU). Both methods can achieve soft start-up with minimum stress and optimal energy delivery. One method is mixed-signal implementation by sensing resonant tank to minimize the digital delay. Another method is digital implementation with look-up table. Experimental results are demonstrated on 500kHz 1kW 400V/12V LLC converter.

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“…The Dual Active Bridge (DAB) topology provides bidirectional dc-dc conversion using two inverters interconnected by an isolation transformer. Thanks to recent improvements in power devices (in particular the development of GaN transistors), the switching frequency of the inverters can be increased, which theoretically allows for a reduction in the size of the transformer according to the sizing relation of the area product (1).…”

Section: Introductionmentioning

confidence: 99%

Design of a Low-Capacitance Planar Transformer for a 4 kW/500 kHz DAB Converter

Demumieux

Aviñó-Salvadó

Buttay

et al. 2019

2019 IEEE Applied Power Electronics Conference and Exposition (APEC)

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Increasing electrification in transport sectors, from automotive to aerospace, highlights the need for low size and high power density components. The recent advent of planar technology theoretically allows to reduce considerably the size of the magnetic components. This article focuses on the design of a high frequency planar transformer intended to be used in a 4 kW 500 kHz DAB converter. In particular, the inter-winding capacitances are assessed, as they have a strong influence on the behaviour of the DAB, and in some extreme cases may impede operation entirely. Analytical and finite element models are used to evaluate the stray elements of the transformer (resistance of the conductors, inter-winding capacitance and leakage inductance), and the resulting circuit model is compared with experimental measurements. This work focuses on influences of design parameters on the transformer stray elements.

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LLC Resonant Converter With Matrix Transformer

Cited by 210 publications

References 17 publications

Optimal Design of Megahertz $LLC$ Converter for 48-V Bus Converter Application

Optimal Design of Megahertz $LLC$ Converter for 48-V Bus Converter Application

Soft start-up for high frequency LLC resonant converter with optimal trajectory control

Design of a Low-Capacitance Planar Transformer for a 4 kW/500 kHz DAB Converter

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