A novel digital control method for shunt active power filter based on line current detection

On the basis of system current detection a novel digital control method for shunt active power filter is proposed. Applying the proposed method to the shunt active power filter in which the pulse width modulation (PWM) voltage source converter is adopted in the main circuit, in the three-phase three-wire system the active power filter can effectively eliminate harmonics of nonlinear load and compensate its reactive current. In this control method only system current and DC side voltage are to be detected and no referential current is needed. Comparing with traditional control methods, the advantages of the proposed method are simple calculation and less operating parameters to be detected. Here, the theoretical analysis and simulation results of the proposed method are given in detail, and a prototype of three-phase shunt active power filter is designed in which the digital signal processor chip ADMC326 is used as the core of the control. The results from simulation and tests verify the feasibility and effectiveness of the proposed method.