An Adaptive Control Method of DC Transformers Imitating AC Transformers for Flexible DC Distribution Application

This paper proposes an adaptive control method for the dc transformer (DCT) of flexible dc distribution system to achieve automatic voltage regulation and bidirectional power transferring like ac transformers in any operation scenario. In the proposed method, each module is controlled at rated voltage ratio mode, thus the input voltage sharing and output current sharing can be realized. Meanwhile, this method does not need the master controller to monitor the operating state, share the signal bus or switch the control method throughout the operating process, so the reliability, flexibility and modularity of the DCT are improved. Besides, the stability of the adaptive method is also analyzed based on the small signal model. Finally, experimental results have verified the excellent performance of the proposed adaptive control method and associated analysis in this work.