Design Procedure of Common-mode Filter for Induction Motor Drive using Butterworth Function

This paper presents improved and simplified methods to design passive EMI filter of the common-mode noise mitigation complied with CISPR 14 or EN 55014; conducted <700 W, Motors. The proposed design procedure of common-mode (CM) filter uses approximation function based on high-order Butterworth function to achieve not only the complied conducted noise but also the transfer function of the filter. This procedure is also based on the knowledge of the base-line of CM filter. The high frequency (HF) current probe is used to measure the conducted noises. Furthermore, this method makes possible a simplicity and fast design of the EMI filter with an arbitrary number of states. Design examples are given and the results are experimentally verified.