Single Phase Voltage Source Converters: Analytical Modeling for Harmonic Analysis in Continuous and Discontinuous Current Conditions

Single-phase voltage source converters are increasingly used in low-voltage distribution systems, but they cause high distortion levels in the feeding systems. This article presents the complete modelling of this converter based on the analytical form of the current harmonics injected in the supply system; the harmonic currents are obtained by Fourier analysis of steady-state current time evolution. Particular attention is paid both to different conduction conditions that characterize the converter behaviour and to when these conditions can take place. The proposed models can be included in a harmonic power flow and allow one to perform harmonic sensitivity analyses of the converter as a function of several parameters characterizing both the fed load and the supply system. Numerical applications are effected in order to ascertain the factors that discriminate the current conduction type and when they can be forecasted to take place.