Phase Current Balancing Control With Single Bus Current Sensor in Three-Phase Dual-Active-Bridge DC–DC Converters

Three-phase dual-active-bridge (3p-DAB) DC-DC converters find widespread application in high-power conversion systems due to their high power density, operational efficiency, and inherent galvanic isolation. However, parameter imbalances in the three-phase transformer of a 3p-DAB can lead to unbalanced phase currents, which may result in unbalanced thermal or current stress on the power devices and reduce the lifetime of both the devices and the transformer, thereby decreasing the reliability of the system. This paper analyzes the unbalanced phase current behavior in 3p-DAB converters and proposes a phase current balancing control method using a single bus current sensor. Compared to multi-sensor control methods, the proposed approach is more cost-effective and enables a more compact converter design. The control strategy reconstructs the phase current trajectories in the αβ frame based on bus current information, then estimates the root-mean-square (RMS) values of each phase current to provide feedback for the closed-loop balance control system. The feasibility of the proposed method is verified through simulations and an experimental platform based on a TI TMS320F28379D microcontroller.