Common-mode Conducted EMI Prediction for Dual Active Bridge Converter Based on Unterminated Behavioral Model

Dual active bridge (DAB) converter is widely used in electric vehicles due to its advantages of electrical isolation function and bi-directional energy flow. However, compared with other converters, the number of switching tubes is large and the internal structure is complex, and the electromagnetic interference at the input and output ends is more serious. In this paper, a predictive behavioral model is established to predict the common-mode (CM) conducted electromagnetic interference (EMI) on both sides of DAB converter. First, the converter is treated as a linear two-port network. Secondly, the impedance of the two-port network in the common-mode loop is calculated from the extracted S-parameters of the converter. And then an equivalent model is established to predict the conducted EMI combined with the common-mode current of the input and output bus. Finally, the proposed model is verified by experiments on a 140W DAB converter system.