Studying the Behavior of 2L Voltage Waveforms Based on Selective Harmonic Elimination PWM

Currently, voltage source inverters (VSI) extensively use pulse-width modulation (PWM) methods with regular impulses within the reference carrier frequency. These methods include the sinusoidal PWM and the space-vector PWM. However, there is an alternative PWM method where individual impulses are not limited by the quantization period of the reference carrier signal and can change in width and position over the entire period of the VSI output voltage within the set symmetry. In research, this method is referred to as the Programmed Pulse Pattern PWM (PPWM). This article analyzes PPWM at selective harmonic elimination (SHE) technique for VSI two-level (2L) output voltage waveforms. SHE is one of the earliest and most widespread PPWM methods that aims at the gradual elimination of lower-order harmonics according to the set number of semiconductor module switchings. During this research, six SHE were calculated for
$2\mathrm{L}$
voltage waveformss with quarter-wave symmetry starting from harmonic 5 and harmonic 7 (for three switchings) and to harmonic 35 and harmonic 37 (for thirteen switchings). PPWM sets were graphically represented as dependencies of switching angles for semiconductor VSI modules and the modulation factor. This article studied the spectra and factors of total harmonic distortions up to harmonic 50 of the voltage over the modulation factor change range from 0 to 1.15 at an increment of 0.01. The most significant results of the research include the dependencies between individual harmonic components and the modulation factor. The results of this research can be used in the development of PPWM methods with SHE for power converters with limited semiconductor module switching frequencies, solving the problems of their electromagnetic compatibility, improving energy efficiency, and optimizing power losses.