Simplified Power Decoupling Control of Triple Active Bridge Converter in Polar Coordinate System for EV Application

The inherent power flows coupling caused by the integrated transformer among multiple ports is challenging for triple active bridge (TAB) converter. To address this issue, a simple but effective power decoupling control for TAB converters is proposed in this article, which universally involves the influence of internal phase shift and can be seamlessly imbedded into other TAB converter optimal control schemes. The TAB converter is modeled in polar coordinates of frequency domain, and the concept of zero-power vector is introduced. By feedforwarding the phase of zero-power vector to the corresponding port, power flows decoupling can be achieved. To further simplify the algorithm, Taylor expansion is performed, and the proposed algorithm is elegantly simplified into a basic arithmetic expression. An 1.5 kW + 0.5 kW prototype is built up for verification, and the proposed control is compared with the state-of-the-art methods quantitatively. The prototype achieved a rate efficiency of 95% with the proposed control. The results show that the proposed control can reduce the computational load by 20 times compared with the conventional power decoupling control and improves the overall suppression performance by 10 dB.