Power Flow Control of Triple Active Bridge Converter Equipped with AC/DC Converter for Constructing Autonomous Hybrid AC/DC Microgrid Systems

We propose an autonomous hybrid AC/DC microgrid system that uses a triple active bridge (TAB) converter as a power routing unit. A TAB converter that can independently control transmission power among three ports is suitable for constructing the microgrid system. We made a prototype TAB converter rated at 400 V, 20 kHz, and 10 kW and demonstrated that it can control the transmission power when the stabilized DC power supply is connected to all three of the ports. A three-port power router that can transmit power between AC and DC is essential for enabling microgrid systems including both power sources. This paper describes an experiment on the power flow control between a three-phase AC source and a lithium ion battery using a TAB converter equipped with an AC/DC converter. The experimental results show that the TAB converter equipped with an AC/DC converter can control the charge and discharge amounts of the lithium ion battery. We also investigated a method for transmission power control between ports having mutually different voltages by controlling the pulse widths of the inverter voltage. The simulation results demonstrated the loss reduction effect of the control method.