Pentacentra Transformer for Multiphase LLC Converter in High-Current Data Center Application
Chang Wang, Mingxiao Li, Ziwei Ouyang, Tiberiu‐Gabriel Zsurzsan, Michael A. E. Andersen
Abstract
The role of data centers has become significant in the era of information technology, and their operation consumes a substantial amount of energy. Therefore, the point-of-load converter or voltage regulation module used in data centers must have high efficiency and power density to deliver a large current to specific servers. A common bus voltage 48 V at the rack stage needs to be stepped down to intermediate bus voltage, which is 6–5 V in this case. To achieve this, a new pentacentra transformer was developed for a four-phase <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter. A centra bar serving as the fifth leg of the core is added to the conventional four-leg matrix transformer. The interleaving and integration of windings in the proposed pentacentra transformer enabled balanced current sharing and reduced conduction loss by 45% compared to the traditional winding layout. The experimental prototype of the converter was designed to achieve 800 W power output at a switching frequency of 500 kHz and 48 V–40 V/6 V–5 V voltage conversion. The peak efficiency achieves 98.1% along with the power density of 240 W/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> with the experimental result. Without the heatsink, the whole converter is operating at rated power within a safe temperature lower than 86°. The excellent thermal performance ensures the reliable operation of the converter and promises a larger power delivery capability.