A new optimal programmed PWM technique [for power convertors]

The paper presents a new method-optimal programmed PWM (OPPWM) technique-which further reduces the harmonic distortion (THD) of the surplus power converter harmonics than those of conventional programmed PWM (PPWM) techniques and ameliorates the amplitude frequency spectrum distribution of the surplus harmonics. The scheme not only inherits many merits of conventional PPWM techniques but also overcomes some shortcomings of conventional PPWM techniques and makes the first crest of the surplus harmonics move backwards; consequently, it diminishes the THD of output PWM waves efficiently. The paper selects the eliminated harmonics number M=13 as an example to express the superiority of the OPPWM technique; moreover, computer simulation has verified the validity of this theory. This technique has many prospects in inverter applications, variable-frequency velocity modulation, VAr compensation and other fields