Application specific harmonic performance evaluation of multicarrier PWM techniques

Various multicarrier pulse width modulation (PWM) techniques suitable for high power converter structures and capable of generating multilevel output voltage waveforms are discussed in this paper. Several interesting characteristics of the multicarrier disposition PWM techniques are revealed. A hybrid multicarrier PWM technique combining the disposition and the phase shifted concepts is considered. The performance of the various techniques with respect to the total harmonic distortion (THD) of the output line voltage in the linear and over-modulation regions is reported. Two distortion factors associated with first- and second-order AC output filtering and for different amplitude modulation indices are presented and used as a measure of comparison for the techniques under consideration