Analytical Approach for Common Mode EMI Noise Analysis in Dual Active Bridge Converter

The increased demand for high power density converters resulted in increased EMI. This is addressed by considering all the converter parasitics along the noise propagation path. In this paper, the analytical approach for common mode (CM) noise analysis of dual active bridge (DAB) converter is presented. The dv/dt of CM voltage that excites the parasitic capacitances are the main source of CM noise. This CM noise is analysed by calculating the change in CM voltage from one state to another state for single phase shift technique (SPST) measured at LISN terminals. The CM noise for symmetrical and asymmetrical inductor and parasitic capacitors are also analysed using this approach. The analysis is thoroughly verified in LTspice with the parasitics measured from the hardware prototype.