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    Solid-State Transformers

    T23.1 - Submodule-Level Decentralized Control for Cascaded Quadruple Active Bridge-Based Medium-Voltage Converters

    Wednesday, March 25, 2026
    1:30 PM - 1:50 PM CT
    Location: 217C
    High-power LVDC loads, such as AI data centers are accelerating the deployment of SSTs that directly interface MVAC to LVDC. This paper proposes a submodule-level decentralized control strategy for an SST comprising a CHB active rectifier on the MVAC side and per-module QAB converters on the LVDC side with local controllers. The proposed strategy eliminates the need for high-fidelity, real-time cross-isolation communication by synchronizing all active bridges to a common heartbeat signal and enabling all controllers to generate independent local control signals. The resultant phase shifts naturally govern power transfer between active bridges, enabling each side to meet its control objectives using only local measurements. Detailed controller design considerations are presented based on a stability analysis. Comprehensive EMT simulations demonstrate tight DC-link voltage regulation, high-quality grid currents, and robust operation under load transients and grid disturbances, without real-time communication among the submodule controllers. These results indicate that the proposed scheme can significantly enhance the reliability, scalability, and flexibility of MV converters.