LAUSR

In this work, the impact of voltage harmonic injection angle on grid current harmonics using a power converter supplied by photovoltaic (PV) array is studied. Converter and PV non-linear operation cause harmonic distortion, which is superimposed to the existing harmonic content of the grid. First, a general mathematical expression connecting voltage harmonic injection angle and current distortion at the same frequency is theoretically proven. This general expression is verified by experimental results for various converter output levels and grid properties, and voltage harmonic injections at various orders and amplitudes. Since the expression is a convex function, there is a unique injection angle that minimises overall current harmonic at the same frequency. The second contribution of this research is that with a minimum of three injections at random angles the parameters of the general expression can be calculated, thus the optimum injection angle can be determined. In comparison to other works, the knowledge of converter harmonic properties, grid harmonic content or grid connection type (inductive, ohmic, mixed) is not needed.