The bipolar DC microgrid is considered in some cases for better integration of renewables and enhancement of system efficiency and reliability. Meanwhile, bipolar high voltage DC is considered to be the next mainstream data center power supply architecture. However, bipolar DC microgrids/architecture faces the challenge of voltage imbalance. This paper proposes a new bipolar single active bridge converter (SAB) based on center-tapped transformer. The bipolar output voltages are clamped by the secondary windings of the center-tapped transformer, thus featuring a load-independent self-balancing characteristic without additional hardware or control effort. Its operation principle and voltage balancing performance are analyzed in detail. The effectiveness of the proposed converter is verified by a 10kW 900V/±400V prototype.
