Inside the Three Phase Common Mode Choke for Variable Frequency Drive Applications

摘要

Attenuation of EMC currents and voltages on outputs of polyphase inverters presents some unique challenges to the simple common mode choke. The function of RFI filters and operating principles applicable to three-phase Common Mode Chokes (CMC) are reviewed along with key principles to consider when designing or specifying a 3 phase CMC. Comparisons, relative to performance, size and cost between the various CMC core materials and winding geometry are demonstrated by design examples, problem solutions and optimization of trade-off factors.