Novel random PWM schemes with weighted switching decision

A new random pulse-width modulation (RPWM) scheme, which includes a weighted decision switching process, has been developed and tested. The switching strategy can be applied to the entire range of the modulation index. The scheme combines the advantages of the deterministic nature of the standard pulse-width modulation (PWM) schemes, and the nondeterministic spread-spectral characteristic of RPWM schemes. Test results have confirmed the improved spectral performance of the proposed schemes over a standard RPWM scheme at both low- and high-modulation indexes.