3.3 kW High-Frequency Full-Bridge LLC DC/DC Converter with SiC MOSFETs

Konferenz: PCIM Europe 2019 - International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management
07.05.2019 - 09.05.2019 in Nürnberg, Deutschland

Tagungsband: PCIM Europe 2019

Seiten: 7Sprache: EnglischTyp: PDF

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Hu, Yuequan; Shao, Jianwen (Wolfspeed/Cree, USA)

This paper presents a 3.3 kW high-frequency DC/DC converter utilizing SiC MOSFETs, intended for telecom and server applications. LLC topology was used because zero-voltage-switching (ZVS) and zero-current-switching (ZCS) can be implemented to improve efficiency. Both simulation and experimental results demonstrated the superior performance of SiC MOSFETs at high frequencies up to 1 MHz. With high switching frequency, the leakage inductance of the LLC transformer can be used without an extra resonant inductor, and the overall size of the converter is dramatically reduced since a smaller EMI filter can also be used. The effects of a PCB layout on current sharing of output rectifiers, parasitic capacitances, and efficiency have been studied. It was also observed that the secondary-side leakage inductance has a great impact on the voltage stress of output rectifiers as switching frequency increases and needs to be minimized.