Triple-Active Bridge-Based Dynamic Power Balancing Solution for Minimizing Overdesigning in Military Aircraft Power System

Military aircraft are an excellent example of custom-designed power grids, powering a mix of both steady and transient intermittent loads. The electrical power system (EPS) in military aircraft like F-35, consists of two sets of 270 V-HVDC buses powering these loads. During real-time operation, switching in of these intermittent loads will lead to unequal loading of HVDC buses, resulting in overloading/underloading of HVDC buses and higher conduction losses on the overloaded bus. For satisfactory performance, both the HVDC buses in the EPS are overdesigned. This anomaly arises because, in the current architecture, there is no provision for controlled power exchange between the two HVDC buses. This article proposes a novel Triple-Active Bridge (TAB) converter-based solution to address this concern without adding extra weight to the overall system. To achieve optimal performance and operational efficiency for bidirectional power flow in HVDC buses, a novel decoupled current control integrated with duty-cycle optimization is proposed. Simulation results validating the decoupled bidirectional power flow control are presented in detail. Compared to conventional control (phase-control alone), the proposed algorithm results in at least a 30% reduction in conduction losses. A 1 kW hardware prototype is developed, and experimental results showing bidirectional power flow and higher operating efficiency are demonstrated.