Study on active power filter used in three-phase four-wire system

An active power filter device used for a three-phase four-wire system is introduced in this paper. The compensation principle and the structure of main control circuits are given. The basic operation principle of the active power filter is analyzed, which is different from that of the active power filter used in a three-phase three-wire system. The experimental results prove the effectiveness of the proposed control method and indicate that the active power filter has good compensation characteristics.