Custom Spectral Shaping for EMI Reduction in High-Frequency Inverters and Ballasts

Abstract

This paper presents the use of frequency modulation (FM) as a spread spectrum technique to reduce electromagnetic interference caused by high-frequency resonant inverters and electronic ballasts. Amplitude modulation (AM) effects due to resonant tank dynamics are counteracted by the use of uniquely shaped modulating waveforms, resulting in the elimination of power spectral density (PSD) distortion and reduced peak currents. Emphasis is placed on shaping the inverter or ballast output current PSD to fit within designated FCC chimneys.