Model Free Predictive Control of a Triple Active Bridge for High Dynamic Performance Without the Decoupling Matrix

The isolated Triple Active Bridge (TAB) DC-DC converter offers high power density, bidirectional power flow control with multiple ports, and galvanic isolation. However, it faces control challenges due to power cross-coupling among ports. The conventionally used decoupling matrix-based controller designed to solve the cross-coupling issue depends on the loading condition and is also parameter-dependent. Moreover, proportional-integral (PI) control is relatively slow and produces large overshoots. To address these issues, this article introduces a model free predictive control for TAB DC-DC converter, eliminating the need for decoupling matrix design. The proposed control strategy can achieve good transient responses even with large parameter and operating point variations. The control consists of two stages: Identification of system parameters and prediction of phase angle using a binary search. Controller simulation verification is done with a MATLAB/Simulink model augmented with PLECS block-set using single phase shift modulation (SPS). Experimental results from a TAB DC-DC converter hardware setup are presented to validate the proposed control methodology, which demonstrates faster response and excellent robustness features.