Random modulated boost converter with improved harmonic spectrum

Higher operating frequency and simpler drive requirements provide rising output power from modern power electronics devices. Nevertheless, switch-mode operation results in electromagnetic interference (EMI) which is produced due to large di/dt and dv/dt. One way to reduce the EMI is the use of classic and expensive input filters or include the active filter into the power circuits. By using randomized pulse width modulation (RPWM), the EMI effect can be reduced and implementation of the proposed control scheme into a boost power converter also improves the harmonic spectrum. Such an approach enables the control of the levels of spectral lines in harmonic spectra. Simulated and measured current spectra, with and without random modulation, are shown in this paper. Such random modulated boost converters have improved harmonic spectra and reduced EMI characteristics.