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Three-Phase Interleaved LLC Resonant Converter with Integrated Planar Magnetics
Fig .1. Schematics of Three-Phase Interleaved LLC Resonant Converter.
The three-phase LLC converter suffers the drawback of numer- ous bulky magnetics. A novel magnetic structure is proposed to inte- grate three inductors and three transformers into one magnetic core, with 600 V GaN devices from Panasonic and 80 V GaN devices from EPC employed for the primary and secondary sides, respectively. By pushing the switching frequency up to 1 MHz, all the windings for the magnetic structure can be implemented with 4-layer PCB winding. And additional 2-layer shielding can be integrated in the PCB windings to reduce CM noise. A 1 MHz 3 kW 400 V/48 V three-phase LLC converter with the proposed magnetic structure is designed with an estimated peak efficiency > 98%, as shown in Fig. 2, and a power density of > 200 W/in3.
Fig. 2. (a) Hardware prototype (b) Estimated efficiency.
