Study of Transient Control Performance of Cascaded NPC-DAB for Power Supply System of Data Center

The cascaded topology composed of a three-level neutral-point-clamp converter (NPC) and half-bridge three-level dual active bridge (DAB) has several advantages such as high voltage level, electrical isolation, and bidirectional power flow. All those merits are suitable for data centers and other applications with large power consumption and high power quality requirements. However, these scenarios require high transient performance of solid-state transformer (SST) systems. In this paper, the control strategies of the SST system under the transient condition are compared, and the optimal control strategy under the transient condition is obtained by analysis and comparison. The feasibility together with the performance improvement is verified by simulation results.