New Method to Predict Common Mode, Differential Mode and Total Conducted Emission for LED Lighting Implement

摘要

Conducted emission detailed in the EMC (Electromagnetic Compatibility) standard consists of vector summation of common mode and differential mode noise, two noise propagation modes, using standard LISN (Line Impedance Stabilization Network). A new method to predict common mode, differential mode and total conducted emission noise is proposed in this paper. Equivalent circuits for common and differential mode noise using mode separable LISN, and for total conducted emission using standard LISN are proposed for LED lighting implements. Common mode, differential mode and total conducted emission noises are calculated by applying noise source voltages and impedances during operation for each mode, and are derived from measurement values using mode separable LISN. Calculated and measured results of total conducted emission with additional impedances C and L in an LED lighting implement are compared. Both results are in good agreement up to 30 MHz, confirming the validity of this prediction method.