Integrated design of EMI filter and PFC low-pass filter for power electronic converters

The design of passive filters for attenuating conducted electromagnetic interference (EMI) is tedious work usually involving a trial-and-error process. It is also possible for the EMI filter that is afterwards equipped to interfere with the function of the original circuit. This perplexing problem is especially critical for a power electronic converter with power-factor correction, which needs another passive filter for removing high-frequency harmonics from the input line current. To solve this problem, an alternative approach with consecutive orthogonal arrays is proposed. Thereby, both EMI noise reduction and power-factor correction are treated jointly by integrating the two passive filters into a single filter. The method with consecutive orthogonal arrays is applied in order to search the satisfactory parameters of the filter and achieve the goals of low EMI noise and high power factor. By virtue of consecutive orthogonal arrays, the number of experiments can be reduced effectively before a set of satisfactory filter components can be obtained. The design procedure and the inferential rules are illustrated by a design example.