Analysis of DC fault for dual active bridge DC/DC converter including prototype verification

This paper presents DC fault analysis for a dual active bridge DC/DC converter which comprises of two active bridges and an internal medium frequency transformer. This topology provides galvanic isolation, voltage step up/ down and bidirectional power transfer. The DC fault study assumes the DC terminal voltage of the converter is at zero . T he steady state fault current is limited to a low magnitude which is less than the rated value without any control ler action depending o n the design of the converter . The DC faults current magnitudes are analyzed with AC equivalent circuit where only the fundamental component of the AC voltages and inductor current are considered . P hase shift and AC voltage magnitude modulation control met hods are selected . A detailed dual active bridge DC/DC converter 3 MW, 4/40 kV based system is simulated using MATLAB/Simulink to validate the proposed analytical study. Further, hardware testing is conducted to confirm the DC fault studies with a 500 W 24 /100 V prototype.