Theoretical and Experimental Evaluation of DC-Circuit Influence in Four-Wire Active Power Filter with Split Capacitor for Strongly Unbalanced Loads

This paper is focused on the influence of the DC-circuit in a four-wire shunt active power filter with split capacitor in the case of strongly unbalanced loads. The quantitative aspects that characterize the power quality in the point of common coupling with a nonlinear and unbalanced load are presented for a concrete case study. After determining the nominal power of the shunt active power filter, the control structure of the compensation system based on the indirect current control is presented. The proposed design algorithm is based on a relationship between the DC-voltage ripple, its frequency, the apparent power of active power filter and the average value of the DC-voltage and on simulation results. The validation of the results is achieved both by simulation and experimentally.