Improved GIRP reference compensation current strategy for hybrid active power filter under unbalanced nonlinear load

Hybrid active power filter has proved to be a useful device to eliminate harmonic currents and to compensate reactive power for nonlinear loads. Several strategies have been proposed to generate the reference compensation current. One of these strategies is GIRP (Generalized Instantaneous Reactive Power Theory) method, which has a good performance in balanced conditions. When file load is unbalanced or the source voltage is distorted, this method is troublesome. This paper presents an Improved GIRP strategy to determine the reference compensation currents of a three phase hybrid active power filler under unbalanced condition. In this method, GIRP strategy is combined with the fundamental positive sequence component of system voltage, which exhibits a better performance compared with the normal GIRP and other similar methods. Proposed method is simulated by MATLAB/SIMULINK. The results are compared with some other strategies; which indicate the proposed strategy Is more effective on compensating of reactive power, harmonic elimination and balancing of unbalanced nonlinear loads.