A novel dual-randomization PWM scheme for power converters

Randomized pulse width modulation schemes in power converters have shown potential for relaxing filtering requirements and reducing electromagnetic interference. Existing schemes invariably randomize one modulation parameter to disperse the harmonic contents of the output of the power converter. This paper concerns the investigation of a new dual-randomization scheme using an analytical approach. The effects of randomizing the two independent modulation parameters, carrier frequency and pulse position, on the harmonic content for a given output of the converter are examined. Analytical and simulation results show the new scheme leads to a further degree of dispersion of harmonic contents when compared with the single randomization schemes.