The iterative learning control strategy for hybrid active filter to dampen harmonic resonance in industrial power system

This paper introduces application of iterative learning control strategy to hybrid active filter with the purpose of damping harmonics resonance in industrial power system. The control strategy can facilitate optimizing performance of damping harmonics resonance due to combination of feedback and feedforward learning control. In the hybrid filter, to obtain the proper reference voltage for voltage-source inverter based active filter, the feedback control scheme mainly focuses on the compensation of reactive power harmonic current and feedforward learning control puts its attention on tracking source voltage distortion and load harmonic current as fast as possible. The control strategy can also simplify configuration of the controller with only source current viewpoints and easy algorithm. The paper still establishes a set of strategy to self-optimizing performance of the system, and presents more useful criteria for identification of stable state of system incorporating reduction of THD of source current corresponding to reference voltage. Some simulation and experimental results based on 12-pulse rectifier system examined are given in the paper.