Short circuit behavior of Dual Active Bridge DCDC converter with low resistance DC side fault

To estimate the short-circuit capacity of future low-voltage DC (LVDC) grids, it is important to determine the transient and steady state short-circuit (SC) current characteristics of DC-DC converter which is an integral part of LVDC grids. The study focuses on the short-circuit behavior of Dual Active Bridge (DAB) topology of DC-DC used for integrating LVDC grid applications like photovoltaic, battery storage systems and interconnecting MVDC to LVDC grids. Different cases are analyzed to estimate the minimum and maximum short-circuit current through DAB DC-DC converter. Simulations are performed by subjecting the DC-DC converter to a low resistance fault at the poles of the secondary side of the converter. The results depict the inherent ability of DAB converter to limit the short-circuit current in the range of rated converter current depending on the phase angle before the fault without turn-off of the semiconductor devices. Based on the rate of rise of SC current, maximum allowable turn-off time of the IGBT devices is discussed for the dimensioning and further analysis of converter control and DC circuit breaker.