The effect of impedance mismatch on the conducted EMI emission

Abstract

The paper proposes a process to predict and analyze conducted electromagnetic interference (EMI) emission using the impedance mismatch approach. Five steps of this process are introduced and analyzed. The impedance mismatch criterion is proposed based on current and voltage waveforms in the time domain. The impedance mismatch fixtures and EMI measured results show how the impedance ratio and conducted EMI emission are related. The work was done using a class E zero-voltage switching (ZVS) resonant inverter at various load conditions - unity, lagging and leading power factors. The experimental results show good agreement with simulated results, which are accomplished by the MATLAB program.