EMI model of an AC/AC power converter

This paper deals with the validation of an EMI model to predict electromagnetic interferences (EMI) produced by power converters. A direct AC to AC matrix converter (MC) has been selected as experimental setup for the paper, but the modeling method can be applied to other converter topologies. The method is based on obtaining a high frequency equivalent circuit, using a combined time and frequency domain approach based on: “EMI source identification→ propagation path impedance→ derived disturbance”. The advantages of the proposed procedure are the computational time reduction and the lack of convergence problems, which may arise when using pure time domain procedures. The paper is focused on the prediction of common mode (CM) EMI of a matrix converter. The simulation results of this case will permit the calculation of currents which leak through the ground connections. Two different EMI sources are compared: one based on PWM waveforms obtained from MATLAB® model and a second one where these data are obtained experimentally from a MC prototype. This procedure allows the comparison of EMI spectra when using simulated waveforms or real source waveforms.