Development of high-efficiency downsized power conversion (380 V to-48 V) equipment for HVDC power supply system

To promote the widespread use of HVDC power supply systems, this paper proposes high-efficiency downsized power conversion (380 V to 48 V) equipment for HVDC use having a size small enough for mounting in the dead space of a rack and describes its performance. Configuring 380 V/48 V conversion equipment with existing technology lowers the efficiency of the entire power supply system and increases the installation area. To solve these problems, it has become necessary to develop equipment with an efficiency of 97 % or greater and with dimensions (W43 x H400 x D80 mm) small enough for mounting in the dead space of a rack. To this end, we have achieved high efficiency and small size by adopting a circuit configuration that uses a compact, high-efficiency chip converter as used on motherboards in ICT equipment and that disconnects the voltage step-up circuit during normal operation. However, a chip converter incorporated in a power supply system may not necessarily operate in a stable manner. To achieve stable use, we performed a stability evaluation while establishing and verifying input/output conditions and taking chip-converter control characteristics into account. We used the results of this evaluation to equip the equipment with the necessary measures to ensure stability.