A novel robust PLL algorithm applied to the control of a shunt active power filter using a self tuning filter concept

This paper presents a novel robust phase locking control scheme for active power filters namely multiple self-tuning filters phase locked loop (M-STFs-PLL). This method uses a multiple self-tuning filters in stationary reference frame to cleanly extract and separate the positive and negative sequences voltage to improve the traditional PLL under highly unbalanced and/or distorted source voltage. The resultant M-STFs-PLL conducts then to a fast, precise and robust positive sequence. To demonstrate the effectiveness of the proposed approach, the direct shunt active power filter control method with the proposed PLL scheme is adopted and its performance is verified by means of simulation with different supply systems.