Influences on resonances between EMI filter capacitors and the utility grid

The differential mode parallel resonance between capacitors of an EMI filter with the inductance of the utility grid is discussed as well as the filters internal common mode resonance. The possibility to excite this resonance with another power electronic circuit is numerically evaluated in frequency domain simulation. The order of magnitude of the generated capacitor current is sufficient to increase the capacitors temperature suggesting accelerated deterioration or even failure of those capacitors.