An active power filter and unbalanced current compensator

This paper presents the synthesis and performance of a shunt active power filter based on the three-phase pulsewidth modulation (PWM) voltage converter connected to the AC mains. Current harmonics and asymmetries caused by nonlinear loads can be compensated. A decoupled system in Park´s variables is achieved and so simple controllers with excellent performance can be used. The controllers are implemented directly in the Park´s referential. Expressions for the controller´s synthesis are derived. Experimental results from a 2 kVA IGBT prototype showing excellent dynamic and steady-state system´s performances are presented. The control circuit is implemented with analog and digital electronic circuits. A considerable amount of electronic circuits are needed. The method presented in this paper can also be implemented with a digital signal processor