Nanocrystalline Core Material for High-Performance Common Mode Inductors

Modern power electronic semiconductors are switching very fast to reduce heat dissipation. Due to parasitic capacitances in the system, for instance, in a motor driven by an adjustable speed electrical power drive system, common mode currents are developed creating electromagnetic interference. The high common-mode current can saturate the core of conventional common mode inductors. Nanocrystalline material shows excellent properties, with high saturation, and high permeability in a broad frequency range. This combination makes them more suitable for common mode inductors than laminated or powder iron, and ferrites. Nanocrystalline material properties are discussed and compared with conventional materials. Common mode inductors for power drives systems have been designed and electromagnetic interference tests have been carried out.