Symmetrical Bipolar Output Isolated Four-Port Converters Based on Center-Tapped Winding for Bipolar DC Bus Applications

Using a multiport converter to integrate renewable energy and energy storage into the bipolar dc bus is a desirable solution due to its high efficiency and reliability. In this article, a series of bipolar output active rectifiers with center-tapped winding is proposed to serve as secondary rectification circuits. Then, a family of isolated four-port converters with symmetrical bipolar outputs is further developed to integrate renewable energy and energy storage. The proposed symmetrical bipolar output isolated four-port converters can achieve single-stage power conversion, symmetrical bipolar output voltage, soft switching, and decoupled control. A typical four-port converter, named full-bridge interleaving bidirectional buck/boost + semiactive rectifier with bipolar output converter, is specifically analyzed in detail in terms of operation principles, voltage and power relationship, port current ripples, soft switching performance, and control. Finally, experimental tests have been performed to verify the feasibility and effectiveness of the proposed topology.