Compensation of AC-DC converter input current harmonics using a voltage-source active power filter

An active power filter should be dimensioned in consideration of the type of nonlinear load if it has no filter. When the load is a thyristor rectifier, the performance of the active filter can be evaluated in the semiconductor switching processes. That is, the currents that the active filter applies are often unable to follow the reference currents during the switching. This becomes all the more critical as the triggering delay angle increases because the switched currents vary even faster. The authors present a theoretical discussion of the relations between the parameters of the active filter and those of the nonlinear load (thyristor rectifier), to obtain the optimum dynamic. The conclusions are then applied to a numerical simulation of an active filter with 150 kVA voltage structure used for compensating the harmonics generated by a 400 kVA rectifier. Finally, the authors present the experimental results obtained from a low-power single-phase model