Planar Transformers in LLC Resonant Converters: High-Frequency Fringing Losses Modeling

Shafaei, Rouhollah; Perez, Maria Celeste Garcia; Ordonez, Martin

doi:10.1109/tpel.2020.2971424

Cited by 34 publications

(15 citation statements)

References 19 publications

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“…The joule losses, which are generated by current, could be reduced with changing the designs, structures or the materials of the wires. Furthermore, the eddy current losses are related to the operation frequency or the leakage fluxes (17) (18) . Due to the above problem, there are studies that have proposed to design an optimized transformer adopted in LLC resonant converters to improve those situations.…”

Section: Introductionmentioning

confidence: 99%

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Reducing Transformer Losses with Adjustable Path-Core Type Inductance in 1.4-MHz LLC Resonant Converters

Noah

Tsuruya³

et al. 2022

IEEJ Journal IA

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Path-core type resonant inductance adjustable (PRIA) transformer usage in high-frequency LLC resonant converters is proposed herein to reduce transformer losses. The proposed magnetic structure is a type of transformer with adjustable resonant inductance combined with a path core for LLC resonant converters. In the proposed transformer, the flux density of the magnetizing inductance can be reduced with a path core. Therefore, fewer core losses are generated when using the proposed transformer. Moreover, the flux of leakage inductance that can be set with the path core has been previously proven by researchers at the Nagoya University laboratory. Consequently, the coil losses, which are one of the largest components of transformer losses, can be reduced effectively by controlling the path of the leakage flux. The proposed PRIA transformer has been reported to improve the efficiency of LLC converters. In this study, a conventional transformer with a magnetic structure is compared with a PRIA transformer through experiments. The core losses were obtained through finite-element simulations, and the coil losses not generated by the magnetic structures were estimated via calculations. The advantage of reducing transformer losses in high-frequency LLC resonant converters with PRIA-structure transformers is presented in this work.

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Section: Introductionmentioning

confidence: 99%

“…Many researchers have tried to provide an answer in ( 19)-( 23) by inventing integrated transformers to be adopted in LLC resonant converters. The transformer losses are can be obtained with FEM simulations (24)- (26) .…”

Section: Introductionmentioning

confidence: 99%

Reducing Transformer Losses with Adjustable Path-Core Type Inductance in 1.4-MHz LLC Resonant Converters

Noah

Tsuruya³

et al. 2022

IEEJ Journal IA

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“…Unlike conventional transformer, in planar transformer (PT), the parasitic elements including leakage inductances and stray capacitances are adjustable and predictable, which are important in passive compensators for imbalances in current sharing of parallel SiC MOSFETs. This will be highlighted when the number of MOSFET devices are [20,21].…”

Section: Introductionmentioning

confidence: 99%

“…It is notable that this method is suitable for mass production and is easily extendable without greatly increasing the volume and price of the original structure. In the following, the merit of the proposed PT are presented: The operating frequency is not limited by skin effect in the proposed PT. It has a less AC winding resistance. Utilizing a greater surface area in the proposed PT will result in improved heat dissipation capability. It contain a low profile, which significantly reduces the height of the structure [20,21]. …”

Section: Introductionmentioning

confidence: 99%

A passive compensator for imbalances in current sharing of parallel‐siC MOSFETs based on planar transformer

Sarfejo

Allahyari

Bahrami

et al. 2021

IET Power Electronics

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SiCMOSFETs are widely employed in power converters due to their high switching speed and low switching loss. However, their low current rating due to the limited active area restricts their high power applications. To apply SiC MOSFETs in high power applications, providing parallel connection is an inevitable choice. To tackle the challenge of imbalanced current sharing problem between parallel SiC MOSFETs, a new passive compensator based on planar transformer (PT) is proposed here. Compared with the conventional transformer compensators, parasitic elements are adjustable and predictable in PT compensators, which is especially important for mass production aims. After explaining the concept of the physical operation of the PT compensator, the whole parasitic elements of the PT compensator are formulated. Based on estimated parasitic elements and using the finite element method (FEM), an optimum PT structure is extracted for imbalances in current sharing of parallel SiC MOSFETs. Afterward, the PT design is discussed in detail and then, a boost converter is constructed. Finally, the experimental results are presented to verify the reliability, accuracy, and effectiveness of the theoretical results.

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“…Moreover, for soft-switching operation, magnetic components stress is much higher due to resonant voltage and current, and in fact, some losses are shifted from semiconductors to magnetics. Recent years, for low power applications (below 5 kW), planar magnetics with low profile are more and more widely adopted in highfrequency converters to reduce the height and volume of converters [18][19][20]. The planar magnetic component can effectively increase the heat dissipation area and its volume is only 20% of that of the conventional winding magnetic component under the same power.…”

Section: Introductionmentioning

confidence: 99%

A Review of High Frequency Power Converters and Related Technologies

Wang

Lucía

Zhang

et al. 2020

IEEE Open J. Ind. Electron. Soc.

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Development of power electronic converters tend to achieve high efficiency and at the same time high power density in many industrial applications. In recent years, with emerging third-generation semiconductor materials i.e. Silicon Carbide (SiC) and Gallium Nitride (GaN), the switching frequency of several MHz has become a widely studied frequency band, therefore traditional technology can no longer meet the demand, and many new challenges appear. This paper presents a comprehensive review of high frequency (HF) converters, the essential challenges are analyzed such as topology selection, soft-switching technologies, resonant gate drivers, magnetic components design and optimization. INDEX TERMS High frequency, converter, soft-switching resonant gate driver, magnetic components.

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Planar Transformers in LLC Resonant Converters: High-Frequency Fringing Losses Modeling

Cited by 34 publications

References 19 publications

Reducing Transformer Losses with Adjustable Path-Core Type Inductance in 1.4-MHz LLC Resonant Converters

Reducing Transformer Losses with Adjustable Path-Core Type Inductance in 1.4-MHz LLC Resonant Converters

A passive compensator for imbalances in current sharing of parallel‐siC MOSFETs based on planar transformer

A Review of High Frequency Power Converters and Related Technologies

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