Practical Implementation of the Zero Harmonic Distortion Converter in Distorted Grids

The Zero Harmonic Distortion converter is a grid-tied converter that can be used in various applications in the metal industry. Its current is sinusoidal and obtained without using a high-frequency rectifier and capacitive filter elements. Instead, there is a three-winding transformer with two converters using selective harmonic elimination (SHE) modulation. However, its use on an already distorted grid presents a challenge to mitigate current distortions. This article discusses the implementation of a new set of angles for SHE modulation that generates a lower level of non-eliminated harmonics and therefore reduces the current total demand distortion (TDD). Experimental results show a TDD reduction of from 7.39% to 2.41% in distorted grids, within the limits recommended by IEEE 519-2022, and a TDD of 2.02% in sinusoidal grids.