Due to advancement in the properties of semiconductor devices, they are widely used in home appliances as well as in industrial applications. The nonlinear property of these devices causes different power quality issues. Harmonic is one of the major power quality issue. To eliminate these harmonics, various technologies have been developed including passive filters, zigzag transformers, active filters etc. Active filters can be used in different configurations such as series active filters, shunt active filters etc. In this work, shunt active power filter has been used to eliminate the harmonics from the system and is based on the instantaneous active and reactive power theory. Pulse width modulation (PWM) current control technique has been used to generate pulses for voltage source converter. PI controller is used to regulate the dc voltage. To obtain the accurate output result, tuning of PI controller parameters (proportionality constant K , integral p constant K) is required. Fractional PI controller has been studied in this paper and its performance has been compared i with the performance of conventional PI controller. The use of fractional order PI controller increases with the passage of time because its performance is better than the conventional PI controllers. It contains one more constant term, called as fractional constant along with proportionality constant and integral constant for the tuning which provides accurate result.