A Novel Decentralized Control Architecture for Power Electronic Transformer Application

Medium-voltage AC to low-voltage DC (MVAC–LVDC) converters are gaining prominence in power electronic transformer applications, such as electric vehicle (EV) charging infrastructure and renewable energy integration, due to their inherent advantages in modularity, scalability, and high power density. These systems typically consist of multiple cascaded or parallel-connected modules, making the design of a robust and coordinated control architecture essential. Effective control must simultaneously address key objectives such as output voltage regulation, intermediate DC bus voltage stabilization, and accurate grid current shaping.Conventional control strategies are predominantly centralized, relying on high-bandwidth communication networks to coordinate among the isolated DC–DC converter modules. While effective in tightly coupled systems, this approach introduces significant complexity, scalability limitations, and potential reliability concerns, particularly under fault conditions or communication failures. In contrast, some decentralized control strategies have been explored to alleviate these issues. However, many of these methods either depend on additional sensing hardware or compromise control bandwidth—especially in the regulation of the intermediate DC-link voltage.To overcome these limitations, this paper proposes a droop-based decentralized control architecture that operates without the need for high-bandwidth communication links or extra sensors. The proposed method is designed to be large-signal valid, ensuring fast dynamic response for both output and intermediate DC bus voltage control across a wide operating range. The control framework enhances system modularity, fault tolerance, and ease of implementation, making it well-suited for practical deployment in modern MVAC–LVDC systems. The effectiveness and stability of the proposed approach are validated through both detailed simulations and experimental results obtained from a 1kW, 230V AC to 250 V DC scaled-down laboratory prototype.