Design of a 20 kW Bidirectional Dual Active Bridge Converter for Aerospace Applications

Transportation electrification has witnessed a trend where the voltage level of the high-voltage DC (HVdc) bus is increasing due to lower cabling weight and run-time losses on the powertrain of an electric vehicle or aircraft. On the contrary, electronic sub-systems close to the passengers stay at low-voltage DC (LVdc) between 12-48 V due to the associated safety risks of being exposed to high voltages. The increase in power demand continues on the LVdc bus continues. These trends indicate the need for DC-DC converters with high voltage-conversion gains, which can efficiently deliver high currents at low voltages. This paper discusses the procedure applied to designing a 20 kW bidirectional dual active bridge (DAB) converter for aerospace applications. The interaction of design targets, design procedures, and regulatory requirements is clarified. The power loss and electromagnetic interference (EMI) modeling method applied in the design of the DAB converter is elaborated. The design optimization method and worst-case analysis for selecting critical components is discussed. Experimental verification of the DAB converter is performed, with an average efficiency of 97.1%.