High Power Density 1 MHz 3 kW 400 V-48 V LLC Converter for Datacenters with improved Core Loss and Termination Loss

Abstract

Power consumption of data centers is increasing rapidly over recent years. Recently, 48V power architecture has attracted more interest in data centers as it offers more efficient architecture. This paper focuses on the implementation of the DC-DC stage of the 3 kW power supply unit. Full-bridge regulated LLC converter is designed with a matrix of two transformers. This paper focuses on the magnetic design of the PCB-based transformer and resonant inductor of the LLC converter. The dimensional effects on core loss are discussed and evaluated. A matrix of two transformers implemented on UI core with rectangular core shape is proposed to minimize the eddy core loss of the transformer core. The termination of the secondary Full-bridge rectifier is also optimized to reduce the conduction loss of the transformer. A low-profile prototype of the designed converter is demonstrated with a peak efficiency of 98% and power density of 700W/in3.