Unlocking the Potential of the Modularized Bridge Rectifier Solid-State Transformer

The Modularized Bridge Rectifier is a promising architecture for Solid State Transformers in Medium Voltage AC to Low Voltage DC applications, thanks to the scalability and modularity obtained by integrating multiple galvanically isolated conversion stages into a standard three-phase diode bridge rectifier. However, the current literature has been limited to unidirectional operation and has not fully explored all the degrees of freedom offered by this conversion structure. Thus, this paper introduces a novel control algorithm to optimize the system performances by fully utilizing the power capabilities of the integrated conversion stages. From analysis and numerical investigations, it is shown that the proposed technique inherently achieves a wider range of active and reactive power transfer for the overall structure, without requiring higher power ratings for the conversion modules. This not only allows enhancing the conversion capability in rectifier mode, but also unlocking four quadrant operation and reactive power control, which can be used to provide additional supporting services to the MVAC grid.