Performance Assessment of a Wide-Bandgap-Semiconductor Dual-Active-Bridge Converter for Electrical Vehicles

Dc-dc converters can be found in different kinds of electric vehicles (EVs). Their main function is to accommodate voltages and currents to the motor or other EV systems requirements. The use of wide-bandgap (WBG) devices can improve the efficiency of silicon-based power converters, qualifying also for higher switching frequencies. In this article the features of a dual active bridge (DAB) converter are studied. The high voltage side of the DAB is implemented with Silicon Carbide (SiC) MOSFETs. For the low voltage side two types of devices are used: either Gallium Nitride (GaN) enhancement high-electronmobility transistors (e-HEMTs) or SiC MOSFETs. The influence of switching frequency and output power on the efficiency are evaluated. The parallel connection of GaN devices is proposed to overcome the device current limits and thus increase the overall DAB converter output power. A feedback controller has been designed to reduce the effects on the output voltage of load changes. The DAB converter evaluation has been realized by using MATLAB/Simulink and PLECS software.