A Piecewise Linearization Approach of Inherent Decoupled Triple-Active Bridge for Power Management of Grid-Connected Renewable Energy Sources

This paper presents a piecewise linearisation approach for synthesising a voltage controller for inherently decoupled Triple Active Bridge (TAB) converters. A case study, capable of managing on DC side renewable energy sources in conjunction with an energy storage system for grid connected application, has been considered. Specifically, a double-PI voltage control architecture has been developed. The control strategy has been outlined, and the control parameters synthesised. A co-simulation study verifies that the design targets have been achieved in terms of control performance. The results are validated by an experimental investigation on a 2.2 kW, 400 V TAB prototype. The resulting controllers demonstrate high dynamic performance and improved coupling rejection across the two TAB output ports, with a broad operational range and step loads of up to 77% of the rated power. Comparing the results with those of a single PI control synthesised using straightforward linearisation shows that the proposed control achieves better performance, preserving control simplicity.