The shunt active power filter (APF) has proved to be a practical device to eliminate harmonic currents and to compensate reactive power for nonlinear loads. This paper evaluates three different control methods of determining the reference compensating current for a shunt active filter that is working under balanced, unbalanced and distorted source voltages. The methods compared are the instantaneous reactive power theory (p-q), the synchronous reference frame method (d-q) and the proposed method. The simulation results are obtained by with Matlab-Simulink. The shunt (APF) and its control methods have been implemented as a prototype and tested through Digital Signal processor (DSP) showing the good performance of the developed active filter. In balanced sinusoidal source voltages, the differences between the results obtained by the three methods are of minimum importance. For unbalanced and distortion source voltage conditions, the results obtained by the methods referenced are quite different. The proposed control strategy has shown the best choice for all situations studied in this paper.