Extraction of Noise Source Impedance of an operating high-power converter with high-EMI noises by increasing SNR using an amplifier

This paper presents analytical expressions for the two current-probe method using an amplifier to extract accurate noise source impedance of an operating power converter. To improve the signal quality of S21-paramter when applying the two-probe method to the power converter in switching operation, a power amplifier is required between the vector network analyzer (VNA) and injecting current probe. For accurate extraction of the noise source impedance of the power converter, however, the effects of the amplifier should be accurately considered in the two-probe measurement method. Therefore, analytic expressions to eliminate the characteristic of power amplifier have been derived in this paper. The proposed method utilizing the derived expressions have been applied to 11 kW on-board charger (OBC) to demonstrate the feasibility of two-probe method in an environment with high-EMI noise.