Minimization of current harmonics content in conventional lighting distribution lines without current sensing

This paper presents a methodology to improve the line current THD of a distribution line configuration with multiple non-linear loads, by means of a simple algorithm based on sensing only the voltage at the Point of Common Coupling (PCC), thus avoiding the use of line current measurement. Firstly, the effect of conventional low frequency electromagnetic lighting ballasts is quantified by means of actual waveforms that yield to a new a circuital model for simulation. The effect on the line current distortion of such loads, generating mainly 3rd and 5th harmonics on the line current, is then studied. Then, the proposed configuration is presented and analyzed, resulting in a significant reduction of these harmonics and also the final THD of the line current. In this work, a scheme of distributed current controlled converters is proposed for mitigating the line current THD. Having the non-linear loads inductive behavior, the proposed control must be implemented using a full bridge topology in order to achieve the requirements of active/reactive power compensation.