Fast Selective Harmonic Mitigation in Multifunctional Inverters Using Internal Model Controllers and Synchronous Reference Frames

This paper presents a fast selective harmonic current mitigation strategy for inverters with active power filter capabilities based on synchronous reference frames and two degrees-of-freedom internal model controllers. The advantage of this control strategy over the conventional proportional integral (PI) control solution is a significant increase in the speed of harmonic detection and mitigation. Furthermore, this control strategy reduces the computational burden when applied in a digital controller. These characteristics make this strategy desirable for applications, where fast/harmonic detection and mitigation are needed. Mathematical analysis and simulations are presented to corroborate the performance of the proposed controller strategy. Finally, the results of this proposal are verified in a 1 kW three-phase multifunctional inverter with harmonic compensation capabilities up to the 17th harmonic.