Decoupled TAB converter with energy storage system for HVDC power system of more electric aircraft

Abstract

It is an important trend to develop the more electric aircraft (MEA) ±270 V high-voltage direct current (HVDC) power system because of its better reliability, power quality and power density. However, there also exists the low-voltage 28 V DC system in HVDC power system, for the aviation battery and some equipment still rely on it. In traditional MEA power systems, battery is only used as a backup power supply, hardly participating in the adjustment of the power system. On the other hand, the function of turbine engine is unidirectional. Hence, it's necessary to add an energy storage port. In this research, the authors put forward the problems of power coupling and strong non-linearity in traditional three-port triple active bridge (TAB) converters, and propose a decoupled TAB topology, which has the feature of decoupled power flow. The topology is compatible with ±270 V DC, 28 V DC and energy storage system with high-power density and efficiency. In addition, the authors unify the efficiency optimisation problem of dual active bridge topology mathematically and provide an optimal parameter design approach for inductance and turns ratio. Simulation results show the power flow control strategy is appropriate for the topology.