Impact of Grid Impedance Variations on Harmonic Emission of Grid-Connected Inverters

TL;DR

This paper investigates how variations in grid impedance can cause resonance issues that amplify harmonics in grid-connected inverters, complicating filter design and system stability.

Contribution

It highlights the impact of uncertain grid impedance on harmonic resonance and emphasizes the need for robust inverter filter design to mitigate these effects.

Findings

Grid impedance variability leads to unpredictable resonance frequencies.

Harmonic magnification can occur due to resonance with uncertain grid conditions.

Design considerations must account for impedance uncertainties to ensure stability.

Abstract

This paper addresses harmonic magnification due to resonance circuits resulting from interaction between uncertain grid impedance and converter. The source of harmonic may be either the grid or inverter. It is demonstrated that unknown and unpredictable grid impedance may result in variable resonance frequency, which challenges robust design of LCL filter of inverter.