High power density high efficiency dc/dc converter

In this paper, the high power density high efficiency trend of DC/DC converter is summarized. Commercial PWM dc-dc converters are discussed based on efficiency. AHB is picked to represent high efficiency PWM converter. To increase the power density, passive Integrated Power Electronics Module (IPEM) technology was utilized. However, PWM dc-dc converters meet some problems when holdup time is required. LLC excels for its low switching loss and low circulating energy at nominal condition. At a high switching frequency, passive integration technology is applied to integrate C_r, L_r, L_m, and the transformer into one module (LLCT). The SR driving method is used, which is based on the body diode forward voltage drop of SR. One 1000W, 800kHz, 400V/48V LLC resonant converter prototype is built based on optimal design procedure, LLCT, and SR drive. The power density of converter is 177W/inch³. The efficiency can reach as high as 96.4%.