Reactive Power Minimization for Modular Multi-Active-Bridge Converter With Whole Operating Range

Multiport power electronic transformers (PET) are widely used in modern power systems to facilitate flexible interconnection between various ac or dc buses, power sources, and loads. However, due to the wide range of “source-load-storage” operating points, achieving efficient operation of the isolated dc–dc converter in the PET can be challenging. This letter focuses on the modular multiactive bridge (MMAB) converter in the PET, and proposes an optimization modulation scheme based on reactive power minimization (RPM) to improve efficiency. The RPM scheme utilizes a simple reactive power open-loop and active power closed-loop control structure that can be modulated online without the use of look-up tables. Importantly, this generalized method not only significantly improves efficiency, but can also be extended to any number of ports. Finally, experimental results are presented to validate the theoretical analysis and effectiveness of the RPM scheme.