INTRODUCING PULSE ANGLE MODULATION FOR INVERTERS

Abstract

This paper introduces three types of pulse angle modulations found to be suitable for application to variable voltage variable frequency inverters, namely: (i) pulse position modulation, (ii) pulse frequency modulation and (iii) pulse repetition period modulation. Their harmonic analyses show very low relative values of low order harmonics, near the reference frequency. Modifications to the second and third types are introduced to further reduce the relative values of low order harmonics. Variation of the magnitude of the reference frequency component is investigated by varying either the modulation factor or the duty cycle. It was proven and verified that varying the duty cycle does not affect the harmonic spectrum near the reference frequency.