Physics-Based Magnetic Modeling of a Three-Port Transformer in a Triple-Active-Bridge Converter with Decoupled Power Flow Regulation
Fei Diao, Guangqi Zhu, Andrew Rockhill, Hui Cao, Yuheng Wu, Yue Zhao
Abstract
Triple-active-bridge (TAB) converter is a promising solution in the smart distributed power management applications, where the three-port high-frequency transformer is the most critical component. This work firstly presents a physics-based magnetic modeling approach for a three-port transformer to investigate its intrinsic magnetic characteristics, especially the high-fidelity magnetic flux density estimation. Then a decoupled power flow control strategy is developed. The proposed magnetic model and the control strategy are evaluated on a 150-kW TAB converter with a high-frequency three-port transformer. The decoupled power control method can effectively reduce the cross coupling among multi-port power regulation. In addition, the transformer flux density dc bias is also identified and it can be reduced significantly using a slew rate control approach.