Soft switching technique for lowering conducted EMI on a three phase boost converter

A new soft switching, three-phase unity power factor boost power converter is evaluated and compared with a conventional hard switching power converter. A special probe was used to trace the propagation of conducted EMI through both power converters. The conducted noise emissions as measured with this probe at various points in these converters are compared with one another. It is shown that the soft-switching power converter generates less noise at the switch and leads to an overall reduction in noise above 2 MHz as measured at the LISN on the mains input