Autonomous DC Microgrid Consisting of Triple Active Bridge Converters

We propose an autonomous DC microgrid consisting of triple active bridge (TAB) converters. In microgrids, various renewable energies, batteries, and local consumer appliances could be integrated by using TAB converters with different operating DC voltages such as 400-V DC bus voltages, 110-V battery systems, and 48-V ICT equipment. We constructed a prototype TAB converter rated at 10 kW and developed a decoupling power flow control system with a voltage difference between each port of the TAB converter. The prototype rated at 400 V/400 V/48 V was implemented to demonstrate the feasibility of the control system. In addition, a linearized model of mutually connected TAB converters was investigated. An experiment using prototype TAB converters was conducted to validate the control system based on the model. When the power flow pattern among the ports of the converters changed in step, the power value of each port converged to the desired power value. Therefore, we conclude that TAB converters can be stably operated by using the developed control system even when TAB converters are connected in series.