A Novel DC-link Voltage Control Method for Comprehensive Power Quality Compensation Inverters

The comprehensive power quality compensation inverters (PQ inverters) combine multiple functions of reactive power compensation, harmonic suppression and three-phase unbalanced compensation, making the dc-link voltage fluctuation of PQ inverters much more complicated than traditional grid-connected inverters. In this paper, the mathematical relationship between the frequency of dc-link voltage ripple and the component of the output currents in PQ inverters is deduced and presented. Furthermore, a novel dc-link voltage control method for PQ inverters is proposed, in which a trade-off between current tracking accuracy and dc-link voltage stability is achieved and the dc-link voltage fluctuation is well suppressed. Finally, simulation and experimental results are presented to verify the effectiveness of the proposed method.