Harmonic current analysis of the active front end system in the presence of grid voltage disturbance

Prediction and control of harmonics injected into the grid from power electronics converters are very important for the power system. This paper analyzes the harmonic currents of an active front-end (AFE) system using its input admittance in the synchronous rotating frame in the presence of voltage harmonics at the point of common coupling (PCC). A voltage harmonic at the PCC of the AFE system with angular frequency of ω may induce current harmonics with angular frequency at not only ω, but also 2ω0-ω. The line angular frequency is ω0. To reduce the induced current harmonics, a grid sensitivity function defined by the grid and AFE impedances should be designed with low magnitude. The proposed analysis and method are validated using simulation and experiments.