Analytical EMI Modeling of an Active Neutral Point Clamped Inverter

This paper studies the electromagnetic interference (EMI) noise modeling for a three-level active neutral point clamped inverter. Although time-domain detailed modeling leads to more accurate results, frequency-domain modeling techniques are commonly used as a faster prediction method. Compared with the conventional differential mode (DM) EMI modeling of power inverters that use only one current source, it is shown that two current sources are required for more precise modeling. A new unified model is proposed for an active neutral point clamped inverter based on the existing equivalent circuit models for common mode (CM) EMI and the developed DM model. Both CM and DM EMI emissions are predicted by the proposed model and compared with the time-domain results. Simulation results indicate that the modeling precision is improved by 56%.