C filters for wide-bandwith harmonic attenuation with low losses

Successful use of traditional (LC and highpass) filters for electric furnaces and other rapidly fluctuating loads can be difficult or impossible due to noncharacteristic harmonic currents produced by these loads. This paper presents the C-filter as an alternative to two or more traditional filters to characteristic and noncharacteristic attenuation over a wide range of frequencies. C-filter advantages and disadvantages are discussed and compared with traditional filters. Design equations and application guidelines for the C-filter are presented.