Non-ideal electric field shielding with grounding resistor for suppressing EMI coupling in a power converter

Shielding techniques are widely applied in suppression of near electric field interference from power converters, so as to enhance their electromagnetic compatibility (EMC) performance. However, sometimes traditional shielding method cannot effectively suppress the electromagnetic interference (EMI) in the full frequency range. In order to make a power converter meet the limit requirement of EMC standard, this paper proposes an improved non-ideal electric field shielding method to balance the suppression effects of the low frequency and high frequency interference. A resistor with appropriate resistance is connected between the shielding layer and the reference ground so as to balance the suppression effect of the high frequency and the low frequency interference. The EMI measurement results show that the power converter with improved shielding method had good EMC performance.