High efficiency N+1 server power supply under light load using integrated Bi-directional converter

Abstract

In this paper, a new power conversion scheme using integrated non-isolated bi-directional converter for the high efficiency N+1 server power supply under light load conditions. By using the snubber circuit, the phase-shift full-bridge (PSFB) converter can apply proposed method under light load conditions. The snubber capacitor is changed to the electrolytic capacitor and each snubber capacitor of the server power supplies is connected via bus for using the auxiliary voltage source and the snubber diodes are changed to switches for operating the bi-directional converter in the secondary side. By operating only the master’s secondary side as buck converter, the core loss in the transformer and the switching loss in the primary side can be decreased. Therefore, the proposed method shows the significantly improved efficiency under light load conditions. The proposed method can be most attractive solution for the redundant parallel power system as a server power system requiring high efficiency under light load conditions. The feasibility of the proposed converter was verified by experimental results with the 1+1 prototypes of 750W, 330~400V input, 12V-62.5A output conditions.