A review on recent effort of conductive EMI suppression methods in high‐frequency power converters

High-frequency power converters with high switching frequency and compact layout are characterised by high power density and high efficiency, which is superior to conventional converters in many aspects. However, the management of electromagnetic interference (EMI) is a significant limitation for their widespread application. Recent conductive EMI suppression methods are reviewed in this paper. The mechanisms and characteristics of the reviewed methods are discussed in detail. Then, the EMI attenuation of the mentioned methods is compared from the perspective of attenuation band, attenuation amplitude, and cost respectively. It is demonstrated that both the source and the propagation path have a significant impact on EMI problems in performance of high-frequency power converters. Several suggestions can be proposed based on the reviewed researches. Firstly, both the potential matching method and the balance winding method in transformer design can achieve a significant EMI reduction at all frequencies within the frequency range of conducted EMI. Secondly, spread-spectrum modulation techniques are suggested to be applied in MHz converters instead of constant frequency control. Thirdly, the reviewed gate driver optimisation methods have a remarkable EMI suppression effect at high frequencies and still work for the suppression of radiated EMI. Finally, filters can have a reduced volume if the reviewed methods are applied.