PCB-Based Magnetic Integration and Design Optimization for Three-Phase LLC
Rimon Gadelrab, Fred C. Lee
Abstract
The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter is the most efficient topology in server and telecom applications. Furthermore, three interleaved <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converters have been shown to yield efficiency advantages at power levels of several kilowatts. The magnetic components of a multiphase <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> , on the other hand, are complex, laborious, and difficult to build cost-effectively. To solve these issues, a high-frequency GaN-based three-phase <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter is used in this research. With GaN working at 500 kHz, all magnetic components, including six inductors and six transformers, can be housed in a single structure, while all magnetic windings are accommodated in a four-layer PCB with 3 oz. of copper. Furthermore, electromagnetic interference can be improved by virtue of three-phase by 20 dB and an additional two layers are added to gain an additional 20–30 dB reduction from a low frequency up to 30 MHz. The proposed construction is simple and economically mass-producible. A 6 kW 400V/48V 3-phase prototype is implemented, with a peak efficiency of over 99% and a power density of 1000 W/in3 (61 kW/L)