An optimized, 99% efficient, 5 kW, phase-shift PWM DC-DC converter for data centers and telecom applications

The development of new power supply systems is increasingly focused on higher efficiency, while the power density should remain on a high level. This is especially true for data center and telecom application Power Supply Units (PSU). The commonly-used DC-DC converter in telecom and data center PSU´s are full-bridge phase-shift PWM converter, which enables a high power and highly efficient conversion, compact design and simple control due to constant switching frequency. The component dimensioning of the converter system has many degrees of freedom, as the design parameters are interdependent from each other to some extend. An automatic optimization procedure based on comprehensive analytical models leads to the optimal design parameters, such as switching frequency and geometry of the magnetic components. In this paper, the development, optimization and design process for an efficiency-optimized 5kW, 400 V to 48..54 V phase-shift PWM DC-DC converter with LC-output filter and synchronous rectification is presented. The proposed optimization algorithm, which considers the part-load-efficiency as well, results directly in the component values for the realized prototype. The design of the converter is explained in detail and measurement results are presented and discussed.