Abstract
Critical systems such as distributed computing systems require high reliability and resilience to ensure the quality of service. Moreover, 90% of all service interruptions experiences by customers derive from the power supply and distribution system. This is because existing distribution systems are centralized and rely primarily on the utility grid. On the other hand, DC microgrid technology is becoming more and more common in buildings, ships, and data center. It promises a change of orientation from centralized to distributed and greener co-generation. However, existing DC microgrid architectures are static, meaning they cannot change their topology after installation. This aspect limits the flexibility and adaptability of the power network to such a heterogeneous and variable scenario.This thesis proposes a novel DC microgrid architecture that enables the concept of "Software-Defined Power Domains". In fact, by using the conceived power crossbar network, the topology can be changed by software dynamically. This aspect improves the flexibility of the power distribution system, which can reconfigure itself to best adapt to loads and sources condition. Moreover, the system's availability is widely enhanced because of the bus redundancy and segmentation provided by the crossbar. Finally, the resilience increases thanks to the dynamic operations able to instantaneously isolate a fault, reconfigure the topology and restore the system's functioning.In this thesis, all the details about this architecture are provided. Then, the control and some dynamic operations are explored and tested by the PSIM simulator to validate the assumptions mentioned above. Moreover, the system's reliability and availability are widely analyzed through Markov chains or Monte Carlo methods when considering components with constant or non-constant failure rates, respectively. Finally, the case study of a DC-powered data center is taken to validate the advantages of the proposed architecture. Several transformations are applied to the basic architecture that gradually improves the availability and MTBF of the system. For instance, the crossbar-based architecture in matrix configuration increases the MTBF of the system by 4 times w.r.t. current architectures. Then, a proposal of an availability-aware power distribution system for data centers based on power crossbars is provided in the perspective, including renewable energy sources combined with batteries able to temporarily supply the data center even in case of failure on the main distribution line.