UPS Operation of Multi-Terminal Smart Transformer for Islanded Operation of Data Centres

With the ever-growing demand of internet-based services globally, the power demand and energy consumption in data centres are consistently rising. To enhance the efficiency of the power conversion stages from the medium voltage (MV) utility grid to the low voltage (LV) level in data centres, smart transformer (ST) provides a prominent solution. Thereby, significantly decreasing the number of cascaded power conversion stages, ensuing lesser complexity, high reliability, high power density/efficiency of data centre power supplies. In this paper, a multi-terminal (MT) ST is proposed for data centres, and particularly its uninterrupted power supply (UPS) mode of operation for continuity of power supply is explored. The MTST is an extension of the ST by replacing the dual-active bridge in the isolation stage with a multi-active bridge. This allows the ST to have multiple LVdc ports which are utilized for server loads in the data centres and also to exchange power from renewable sources/energy storage systems. The MTST can also be operated as an UPS at times of power outages. The simulation of the proposed system is done in PSCAD software to verify its operation in UPS mode, ensuring uninterrupted power to the data centres.