The nonlinear load connected to a three-phase currents source will cause distortion. In order to reduce the distortion, a three-phase active filter system is used. Reduction is carried by the compensation current. The proportional integral (PI) control is often used to control the compensation current. Development of pulse width modulation rectifiers connected to the PI control can produce a pure sinusoidal current source. Compensating current control is also done by Akagi instantaneous power theory approach. Beban nonlinier yang dihubungkan dengan arus sumber tiga fase akan mengakibatkan distorsi. Untuk dapat mereduksi distorsi tersebut digunakan filter aktif sistem tiga fase. Reduksi dilakukan dengan mengkompensasi arus. Dalam pengaturan arus kompensasi digunakan kendali proporsional integral (PI). Pengembangan kendali PI terhubung penyearah modulasi lebar pulsa (MLP) menghasilkan arus sumber sinusoida murni. Pengendalian arus kompensasi dilakukan juga dengan pendekatan teori daya sesaat Akagi.