Shaping control strategies for active power filters

This study presents a general control strategy for active power filters derived from the current-shaping principle previously employed in shunt active filters. The generalisation introduced here and denoted as voltage-current shaping control, exploits the symmetry between the possible wave-shaping solutions, and can be applied to shunt, series, and more complex networks of active filters. Moreover, the proposed generalisation allows the synthesis of specific control schemes with a reduced number of sensors. The relevant properties of the proposed schemes in the application of harmonic mitigation are determined. Further, a discussion of the integration of multiple quasi-resonant schemes is presented. Using this approach, it is possible to fine-tune the mitigation of specific components in the harmonic profile from the voltages or currents in the circuit. Experimental results obtained from using a 1kVA prototype are presented to support the proposed generalisation.